Regex in validation is proven technology, so since you have a complex form, likely some other part/function on the form will be the reason. Do some bughunt by copying the form bit by bit to another new blank form, starting with a simple single attribute and a save button, which probably works fine. You will soon know which element is causing the damage.
I think you’re looking for the “Abort on Validation Errors” setting:
Please check your event handlers, especially BeforeCommit, BeforeDelete and BeforeRollback They must be raising errors, try and uncheck the “Raise an error when microflow returns false”
From your description it looks like these event handlers are interfering in the process flow
Did you find a solution finally?
I'm facing the same problem and I don't find a solution…
No I did not find an answer. The answer is that validation rules on domain level do not work in complex situations.
Maybe the behaviour changed. I am not up to date.
You can work around this problem with microflow validation in your form. When a user has filled all the information in your form and want to confirm the data you can start a microflow to check the data.
Hope that can help you