Pluses added to tags if I have to check another source in Add Books

I added a bunch of books through the Add Books page. In each case, I put the appropriate tags into the Tags to Add box before I searched. On several of the books, my default search (Overcat) came up blank, and I clicked through one or more of the sources in my source list (in the list that shows up on the right if the search is blank). I got at least one from a library, though most from Amazon. And when I selected a book from a successful search, and it was added, the tags (all, or all but the first one) had a + in front of them. ie, I'd enter "Fic, Mystery, !Sale.FOAFL, __scan_cover"; search, and end up finding it on Amazon.com; and the entered book had, as tags, "Fic, +Mystery, +!Sale.FOAFL, +__scan_cover". I deleted all the added pluses, but I don't think it would be hard to reproduce.

When you search for a book by words (title/author), if you don't find anything, the next search (done by clicking a source link) shows at the top of the right pane with + in front of each word. Is this the same thing, or related? But it shouldn't be writing the pluses into the book record.

There's another bug thread for this, I think, somewhere... I just need to hunt it down..

Aha! Closing as a duplicate of https://www.librarything.com/topic/349508#8101328, but I will bump that thread with this reference.

Thanks! I looked, but didn't see it.