Did you see the release notes for 7.23.2? https://docs.mendix.com/releasenotes/desktop-modeler/7.23#7232
This part might solve your problem:
We fixed an issue where custom widgets that subscribe using the this.subscribe
function and unsubscribe using mx.data.unsubscribe
got an error when calling mx.data.unsubscribe
. (Tickets 79881, 80075, 80078, 80174)
Regards,
Ronald
Multiple widgets are affected by 7.23 and are throwing similar errors to yours.
See for example: https://forum.mendix.com/link/questions/92868