When adding a book/edition, if you fill out the form and there's an input error (e.g. a dash in the ISBN copied from elsewhere), the form will reload with an error message at the top and also silently dropping some of your input. (In my last attempt: cover and publisher disappeared, and then an extra copy of the author's name was added for some mysterious reason — this was on MacOS Safari 14.0.3 fwiw.)

I've accidentally saved books without a cover due to this bug a few times. It would be nice if the form could display errors without losing anything!