Hello,
This is really an extension of the discussion from this thread.
https://forum.osticket.com/d/94440-custon-form-in-default-help-topic-and-incomming-tickets

I've noticed the same behavior in v1.14.3, where tickets that are created via incoming emails do not have Custom Forms applied to them. I understand that the current behavior is that the Custom Form is only applied if the ticket is created via web portal with the appropriate Help Topic, but I guess I regard this as a defect (nothing derogatory intended there). If the Help Topic is set as the default for the Email account, and the Custom Form is attached to that Help Topic, it seems appropriate that osTicket should apply the custom form to the resultant ticket automatically for a message sent to that mailbox. I'd suggest an amendment to the code base to apply the Custom Forms automatically if configured as such. Thanks for your consideration.