Some strange things are happening with the submission forms…
Add Book: when clicking the Language button, almost all the fields disappear.
Add Book+Edition: when clicking the Add Credit button in the Edition part, a bunch of fields get duplicated.
This is happening on two different browsers (Chrome & DDG).
Sorry about that. I’ll get this corrected soon, definitely today.
This sounds like what I was experiencing with BUUUUG! What's going on with adding an author to a Book?
Good use for the raw edit 
Exactly, fixing that BUUUUG inadvertently created this new bug. It’s fixed now. And I’m looking at ways to test the form for thoroughly.