Added book to publisher series, combined two entries of same book, lost series entry

Added book to publisher series, combined two entries of same book, lost series entry.
Appears to be a bug? I've seen it more than once but can't recall the last one.
Example I just experienced:
Manually added Dear Dr. Dynamite
by Harvey R. Greenberg
to my catalogue. Added to https://www.librarything.com/nseries/258667/Scholastic-Apple-Paperbacks
Checked author's page, added two entries for the book to workbench, combined, checked book page, publisher series entry had disappeared after combining.
It's late... I'll add it tomorrow. Adding to a large series list is sooooo slow.
In contrast to adding to a large list. I mentioned that in feature improvements.

I don't believe this is a bug. I believe this is an RSI to not lose anything, but right now functions as expected. Whichever book is the top most book has its details saved. Secondary books lose their series information.

I see that Dear Dr. Dynamite only has 3 copies after combination. If the series was attached to the work with fewer copies when you combined them, it is lost. There is a warning about that on the combination page.

OK thanks. Did not notice (especially when doing hundreds of these things).

The original bug report from almost three years ago: https://www.librarything.com/topic/335019

See update at https://www.librarything.com/topic/335019#9053190