I have been looking to set up a rule when transitioned a sub task is created and assigned to a user in a custom user picker field. This seemed to work fine at first, when trying to add some additional automation rules it then stopped. I have disabled all other rules and cut a shorter automation rule to allow this to run but I keep getting the below error message;
"Unknown fields set during create, they may be unavailable for the project/type. Check your custom field configuration. Fields ignored -Assignee (assignee)"
I have set this to a global and a project level automation rule but still no success, I am not sure what was changed to cause this to stop working, the Assignee field should take from a specific user field and as mentioned this had been working previously.