Thank you, Craig.
Peter replied that’s normal behavior of BigTimer.
So, as solution, I just over-passed the BigTimer node, connecting parse_timeout straight to switch control. All works now, every day 
Code here, maybe helpful for someone.
[
{
"id": "6491080e.1afc78",
"type": "ui_switch",
"z": "669e4b2e.c077d4",
"name": "enable_water",
"label": "Enable Watering",
"group": "e6e9e9c5.46a0c8",
"order": 1,
"width": 0,
"height": 0,
"passthru": true,
"decouple": "false",
"topic": "shm/garden/water/enable",
"style": "",
"onvalue": "on",
"onvalueType": "str",
"onicon": "",
"oncolor": "",
"offvalue": "off",
"offvalueType": "str",
"officon": "",
"offcolor": "",
"x": 120,
"y": 720,
"wires": [
[
"82219b7f.5ef6e8"
]
]
},
{
"id": "82219b7f.5ef6e8",
"type": "change",
"z": "669e4b2e.c077d4",
"name": "switch2timer",
"rules": [
{
"t": "change",
"p": "payload",
"pt": "msg",
"from": "off",
"fromt": "str",
"to": "stop",
"tot": "str"
},
{
"t": "change",
"p": "payload",
"pt": "msg",
"from": "on",
"fromt": "str",
"to": "auto",
"tot": "str"
}
],
"action": "",
"property": "",
"from": "",
"to": "",
"reg": false,
"x": 150,
"y": 760,
"wires": [
[
"45189448.b43a1c",
"339a41b2.52fd0e",
"a6e8ed21.e3a26"
]
]
},
{
"id": "9752622f.768e6",
"type": "inject",
"z": "669e4b2e.c077d4",
"name": "water_sch_on",
"topic": "shm/garden/water/enable",
"payload": "on",
"payloadType": "str",
"repeat": "",
"crontab": "",
"once": true,
"onceDelay": 0.1,
"x": 100,
"y": 680,
"wires": [
[
"6491080e.1afc78"
]
]
},
{
"id": "b8860b8c.1579e8",
"type": "inject",
"z": "669e4b2e.c077d4",
"name": "init_off",
"topic": "",
"payload": "off",
"payloadType": "str",
"repeat": "",
"crontab": "",
"once": true,
"onceDelay": "0.05",
"x": 370,
"y": 920,
"wires": [
[
"c413f53e.29ef58",
"c5ae1192.32ff4",
"b52a0805.d13df8"
]
]
},
{
"id": "c413f53e.29ef58",
"type": "exec",
"z": "669e4b2e.c077d4",
"command": "actuators/valve.py -i 2 ",
"addpay": true,
"append": "",
"useSpawn": "false",
"timer": "",
"oldrc": false,
"name": "",
"x": 560,
"y": 920,
"wires": [
[
"fcd2d087.c8a49"
],
[],
[]
]
},
{
"id": "fcd2d087.c8a49",
"type": "debug",
"z": "669e4b2e.c077d4",
"name": "watering",
"active": true,
"tosidebar": true,
"console": true,
"tostatus": false,
"complete": "payload",
"x": 770,
"y": 960,
"wires": []
},
{
"id": "a138f48e.2bbb08",
"type": "mqtt out",
"z": "669e4b2e.c077d4",
"name": "",
"topic": "",
"qos": "",
"retain": "",
"broker": "2bd2afca.e962e",
"x": 810,
"y": 1020,
"wires": []
},
{
"id": "339a41b2.52fd0e",
"type": "bigtimer",
"z": "669e4b2e.c077d4",
"outtopic": "shm/garden/water_tree/state",
"outpayload1": "on",
"outpayload2": "off",
"name": "TreeTimer",
"lat": "32",
"lon": "34",
"starttime": 5001,
"endtime": "10090",
"startoff": 0,
"endoff": 0,
"offs": 0,
"outtext1": "on",
"outtext2": "off",
"timeout": 1440,
"sun": false,
"mon": false,
"tue": true,
"wed": false,
"thu": false,
"fri": false,
"sat": true,
"jan": false,
"feb": false,
"mar": false,
"apr": false,
"may": true,
"jun": true,
"jul": true,
"aug": true,
"sep": true,
"oct": true,
"nov": false,
"dec": false,
"day1": 0,
"month1": 0,
"day2": 0,
"month2": 0,
"day3": 0,
"month3": 0,
"day4": 0,
"month4": 0,
"day5": 0,
"month5": 0,
"d1": 0,
"w1": 0,
"d2": 0,
"w2": 0,
"d3": 0,
"w3": 0,
"d4": 0,
"w4": 0,
"d5": 0,
"w5": 0,
"suspend": false,
"random": false,
"repeat": false,
"atstart": true,
"odd": false,
"even": false,
"x": 380,
"y": 980,
"wires": [
[],
[],
[
"3ce33470.31935c",
"a138f48e.2bbb08",
"c413f53e.29ef58"
]
]
},
{
"id": "3ce33470.31935c",
"type": "ui_switch",
"z": "669e4b2e.c077d4",
"name": "",
"label": "Water Trees",
"group": "e6e9e9c5.46a0c8",
"order": 6,
"width": "5",
"height": "1",
"passthru": false,
"decouple": "true",
"topic": "shm/garden/water_tree/state",
"style": "",
"onvalue": "on",
"onvalueType": "str",
"onicon": "nature",
"oncolor": "green",
"offvalue": "off",
"offvalueType": "str",
"officon": "nature",
"offcolor": "grey",
"x": 120,
"y": 1020,
"wires": [
[
"d6f61713.adc4b8"
]
]
},
{
"id": "d6f61713.adc4b8",
"type": "function",
"z": "669e4b2e.c077d4",
"name": "parse_timeout",
"func": "// Outputs:\n// Counter_to_display, GPIO control via BigTimer, Counter_to_process\n\ntry{\n var delay = flow.get('get_water_timeout');\n} catch (er) {\n var delay = 10;\n}\n\n// Block loop of messages when off\nvar prev = flow.get('prev_tree_msg') || {payload: 'ignore'};\nnode.status({fill:\"green\",shape:\"ring\",text: delay+','+prev.payload+','+msg.payload});\nif ('off' == msg.payload && 'off' == prev.payload) return [null, null, null];\nnode.status({fill:\"green\",shape:\"dot\",text: delay+','+prev.payload+','+msg.payload});\n\n// Keep msg for next round\nflow.set('prev_tree_msg', msg);\nif ('on' == msg.payload) {\n // Set delay, start countdown, on load\n var m1 = {payload: delay};\n return [m1, msg, m1]; \n} else if (('off' == msg.payload) || (msg.payload <= 1)) {\n var m1 = {payload: 0};\n if ((msg.payload <= 1) && (0 == delay)) { // request never off\n return [m1, null, m1];\n } else {\n // off load, reset clear counter\n return [{payload: ' '}, {payload: 'off'}, null];\n }\n} else if (msg.payload > 1) {\n // decrement countdown\n var m1 = {payload: parseInt(msg.payload)-1};\n return [m1, null, m1];\n}\n",
"outputs": 3,
"noerr": 0,
"x": 170,
"y": 1080,
"wires": [
[
"d25b362a.630378"
],
[
"3ce33470.31935c",
"c413f53e.29ef58"
],
[
"a1168f85.09676"
]
]
},
{
"id": "d25b362a.630378",
"type": "ui_text",
"z": "669e4b2e.c077d4",
"group": "e6e9e9c5.46a0c8",
"order": 7,
"width": "1",
"height": "1",
"name": "counter",
"label": "",
"format": "{{msg.payload}}",
"layout": "row-right",
"x": 390,
"y": 1060,
"wires": []
},
{
"id": "a1168f85.09676",
"type": "trigger",
"z": "669e4b2e.c077d4",
"op1": "",
"op2": "",
"op1type": "nul",
"op2type": "pay",
"duration": "1",
"extend": false,
"units": "min",
"reset": "",
"bytopic": "all",
"name": "",
"x": 190,
"y": 1140,
"wires": [
[
"d6f61713.adc4b8"
]
]
},
{
"id": "7cd4b83b.e9d328",
"type": "function",
"z": "669e4b2e.c077d4",
"name": "UI_to_flow_context",
"func": "flow.set(\"get_water_timeout\", msg.payload);\nreturn null;",
"outputs": 1,
"noerr": 0,
"x": 740,
"y": 1280,
"wires": [
[]
]
},
{
"id": "7998052f.fd021c",
"type": "ui_slider",
"z": "669e4b2e.c077d4",
"name": "timeout",
"label": "Stop in {{value}} min",
"group": "e6e9e9c5.46a0c8",
"order": 3,
"width": 0,
"height": 0,
"passthru": true,
"topic": "/shm/garden/timeout",
"min": 0,
"max": "90",
"step": 1,
"x": 550,
"y": 1280,
"wires": [
[
"7cd4b83b.e9d328"
]
]
},
{
"id": "aff2deab.9a23a",
"type": "inject",
"z": "669e4b2e.c077d4",
"name": "",
"topic": "",
"payload": "10",
"payloadType": "num",
"repeat": "",
"crontab": "",
"once": true,
"onceDelay": 0.1,
"x": 400,
"y": 1280,
"wires": [
[
"7998052f.fd021c"
]
]
},
{
"id": "e6e9e9c5.46a0c8",
"type": "ui_group",
"z": "",
"name": "Garden: Watering",
"tab": "531ef1f0.9a426",
"order": 3,
"disp": true,
"width": "6",
"collapse": false
},
{
"id": "2bd2afca.e962e",
"type": "mqtt-broker",
"z": "",
"name": "",
"broker": "localhost",
"port": "1883",
"clientid": "",
"usetls": false,
"compatmode": true,
"keepalive": "60",
"cleansession": true,
"willTopic": "",
"willQos": "0",
"willPayload": "",
"birthTopic": "",
"birthQos": "0",
"birthPayload": ""
},
{
"id": "531ef1f0.9a426",
"type": "ui_tab",
"z": "",
"name": "MyDashboard",
"icon": "home"
}
]
The valve/switch control script is here.
An alternative solution was:
Every time the UI control is taken, the parse_timeout should send 2 messages to the BigTimer: Manual + On or Off + Auto respectively.
This can be done with node.send() command (async messaging).
Advantage of this method versus current solution: MQTT receives manual on/off commands too for registration.
Disadvantage: more code, longer run time.
