I've found some bugs (reported several of them, waiting to hear back from support), but wanted to give others a heads up on what I am seeing.
If you try to drag an element or field on to the form, and it disappears, or didnt get placed like you think it should, often I think the form thinks the element was added (behind the scenes), but the UI doesnt pick up on it.
Once you add these "phantom" elements, the form gets all kinds of borked. It will work for what had been built to that point, but you can no longer import it without receiving errors, often you lose the ability to view/open the properties of individual elements, and even lose the ability to add new elements.
I'm having to do ALOT of rework right now when this is going on