Forms not opening in Fullscreen from list view

Hi, I have a specific form that, although it's saved to open in full-screen, defaults to the SharePoint new/edit and display.

The direct NewForm.aspx links works. It will open in either Panel or Dialog but not Full-screen. This does not seem to be the case with other forms thankfully. Is there anything that would have caused this reaction?
Thanks

Dear @flowy,
A few things you can check. First of all, check the List Settings, make sure default forms are selected, that's what you should see for our forms to work:

Secondly - check the Content Type. Make sure the right Content Type is selected, and also make sure it's not corrupted by including some broken lookup field or anything else along these lines.