Hello there.
Found a possible bug and would like to know if anyone else is having the same problem.
Forms and Request Types are not interacting as expected.
In the Forms section of Project Settings you can see a list of your forms, and the request types you have attached them to. When editing forms, you can attach them to request types in the settings using the 'Attach to request types' toggle and dropdown. You can use this to add, change, or remove the request types the form is attached to. From the list view of all the forms, the changes you make appear to happen as expected.
HOWEVER,
When you then go to create a ticket using a request type, in the Issue View instead of using what you have just set in the Forms section, it will continue to use the form it was previously using. This includes if you remove all forms.
One interesting side note, is that if you instead edit the content of one of the stuck forms, it will be changed when you create new tickets.