Its working for me
Example Flow
[{"id":"d61f4d428d068cd7","type":"inject","z":"54efb553244c241f","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"[\"Intrusion\",\"Alarm\",\"Input\"]","payloadType":"json","x":260,"y":1800,"wires":[["3f22d122d79c0faf"]]},{"id":"3f22d122d79c0faf","type":"switch","z":"54efb553244c241f","name":"Alarm","property":"payload[1]","propertyType":"msg","rules":[{"t":"eq","v":"Alarm","vt":"str"}],"checkall":"true","repair":false,"outputs":1,"x":410,"y":1800,"wires":[["fdf8a1d049967a2d"]]},{"id":"fdf8a1d049967a2d","type":"debug","z":"54efb553244c241f","name":"debug 29","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":580,"y":1800,"wires":[]},{"id":"82d1b19984d0c573","type":"inject","z":"54efb553244c241f","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"[\"Intrusion\",\"Alarm\",\"Input\"]","payloadType":"json","x":270,"y":1900,"wires":[["782adf6649f8460d"]]},{"id":"782adf6649f8460d","type":"switch","z":"54efb553244c241f","name":"Alarmmmm","property":"payload[1]","propertyType":"msg","rules":[{"t":"eq","v":"Alarmmmm","vt":"str"}],"checkall":"true","repair":false,"outputs":1,"x":430,"y":1900,"wires":[["a73f5ba2dee9358c"]]},{"id":"a73f5ba2dee9358c","type":"debug","z":"54efb553244c241f","name":"debug 30","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":580,"y":1900,"wires":[]}]
maybe your array is not an array but a string ?