Rescanning book to put it in an extra collection resets all other collections

Today I was moving books to work. To keep track on what is there I have a collection 'located at work'. Now I thought I could quickly add the books in there by using the scanner and configuring to only set that collection to avoid the 'duplicate copy' warning or having to search them one at a time. But now the result was that they were all ONLY in that category, while I expected it to be adding it.
Thinking back, I could imagine this being by design, but then it would be helpful for cases like this that you want to track moving a stack of books (like lending it to a friend or so) to be able to scan and add to collections instead of set all collections (especially as you get duplicate book warnings if you scan something for the 2nd time to 'your collection' so there it does not override but add.)

Not a bug. This is how it works. Changing it would make things worse for most users.

You change collections by changing the collection on the book. (Various places to do that.)

For lending to a friend you can use the circulation feature.

>2 MarthaJeanne: For lending to a friend you can use the circulation feature.

Or many other mechanisms, such as tags. As MarthaJeanne says, this is the way it works. Sometimes you just gotta live with the way the rules are set up. :-) There is no "right" way, but this is the system that LT has adopted, and it works for most people.

then why does it override the existing one, I would then expect to get a duplicate report as I get a 2nd instance

Can you give one example of a book where that happened in your catalog? Now that we have book history, the devs may be able to figure out what really happened based on that (maybe it just added a second uncombined copy, maybe something else is going on).

For example this one https://www.librarything.com/work/4410345/book/315456861

And I have been searching on title to see if it was now duplicated but that wasn't the case: https://www.librarything.com/catalog/Tobywuppes?&deepsearch=uml

And what I just realized is that it probably also lost all tags due to this.

>6 Tobywuppes: So you are sure you had another copy of that book in your catalog before you added it on June 4? Because I can't see any UML books that were deleted around that time.