I have taken out the HA nodes and replaced them with Inject nodes so that it can be tested without the HA nodes and it works ok for me.
Which version of node-red are you using? Edit: Also tell us the nodejs version, the command node -v will tell you that.
Are you sure it is the Join node that is showing the error? Can you do a screenshot of the error?
For the future please see this post for how to share flows here, it makes it easier to copy them if you do that. How to share code or flow json
Here is my flow, does it fail for you?
[{"id":"8cc48f57.6aaf7","type":"function","z":"84405ff5.25fa6","name":"Outside Temp prefix","func":"msg.payload = \"It is\" + msg.payload + \"degrees outside\";\nreturn msg;","outputs":1,"noerr":0,"x":400,"y":2140,"wires":[["c2e216ec.273778","6e846956.116f08"]]},{"id":"16a3a357.5bb1cd","type":"function","z":"84405ff5.25fa6","name":"House Temp prefix","func":"msg.payload = \"and\" + msg.payload + \"degrees inside\";\nreturn msg;","outputs":1,"noerr":0,"x":550,"y":2040,"wires":[["4539666.d209598","6e846956.116f08"]]},{"id":"c2e216ec.273778","type":"change","z":"84405ff5.25fa6","name":"","rules":[{"t":"set","p":"topic","pt":"msg","to":"1","tot":"str"}],"action":"","property":"","from":"","to":"","reg":false,"x":590,"y":2140,"wires":[["a8511133.286cb"]]},{"id":"4539666.d209598","type":"change","z":"84405ff5.25fa6","name":"","rules":[{"t":"set","p":"topic","pt":"msg","to":"2","tot":"str"}],"action":"","property":"","from":"","to":"","reg":false,"x":750,"y":2040,"wires":[["a8511133.286cb"]]},{"id":"a8511133.286cb","type":"join","z":"84405ff5.25fa6","name":"Output Test","mode":"custom","build":"object","property":"payload","propertyType":"msg","key":"topic","joiner":"","joinerType":"bin","accumulate":false,"timeout":"","count":"2","reduceRight":false,"reduceExp":"","reduceInit":"","reduceInitType":"","reduceFixup":"","x":850,"y":2100,"wires":[["6e846956.116f08"]]},{"id":"6e846956.116f08","type":"debug","z":"84405ff5.25fa6","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","x":690,"y":2320,"wires":[]},{"id":"0cc9d49e1b988ba6","type":"inject","z":"84405ff5.25fa6","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":210,"y":2040,"wires":[["16a3a357.5bb1cd"]]},{"id":"ba4f029073cd74ba","type":"inject","z":"84405ff5.25fa6","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":200,"y":2140,"wires":[["8cc48f57.6aaf7"]]}]
