@adixon Actually in my case it really had to do with the group being set.
We have a webform like the following
+ Existing Contact - Contact name
+ Existing Contact Household - Contact name filtered by Group
If I set this as empty it's just fine, and when I traced it it seems like the #group is a reserved name used already thus causing this error. Maybe I'm wrong here though.
Hey folks,
This is still an issue actually. I had a heck of a time trying to figure out where the stacktrace issue was coming from. Is there any reason we can't use a different variable than group. I think it's a useful function but presently I can't use it for a client because of this issue.
Warning: explode() expects parameter 2 to be string, array given in Drupal\Core\Form\FormErrorHandler->setElementErrorsFromFormState()
ShaneOnABike → created an issue.