IMO it's a nasty bug.

There's a sort command in the Bookmarks Manager, so the user can have it sorted if they want. Just add another option - Don't Sort. Then you don't force a particular choice of orders (or two choices, in this case - by name or by date) on the user. Suggest it, perhaps, by making it the default. But don't force it.

(This isn't just a quibble of UI philosophy. I imported 1,000 bookmarks. I can't find anything, and what I can find takes too long to get to.)

Any chance this might change back? Who do I ask?