This is not a regression. Tested in //UE5/Release-5.0 cl20979098.
Camera bookmark modifications are not saved unless it is a new bookmark.
From the user reporter:
"FBookmarkTypeToolsImpl.CreateOrSetBookmark appears to be the only area of the bookmark code that calls Bookmark->Modify to mark the package dirty. and this code path is only when a new bookmark is created. If a bookmark of the appropriate type already exists in that slot, Modify does not get called, even though higher up the callstack, the bookmark is updated with the new view location"
The camera moves to the updated book marked position from step 7
The camera moves to the original book marked position from step 4
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-171741 in the post.