Hello,
I created my own sample adding built in functions and Custom functions with the latest build of Spread and EditError event occurs in both the cases.
Please have a look at the attached sample and video depicting the same and let us know what are we missing to replicate the issue.
Hope it helps. Else please send us the working sample replicating the issue for us to debug the same at our end and proceed further on this.
Thanks,
Reeva