Bulk-add tags sometimes fails

[shish]

(Copy-pasting from an email I got sent so it doesn't get lost)

Using the tag widget in the sidebar "bulk actions" panel. Sometimes, though confusingly not all the time, it'll choke if told to add (as opposed to replace) a tag but one of the target posts already has the tag. One example is trying to add the AI-generated tag to this search, which yields this:
Internal Error

Message: SQLSTATE[23505]: Unique violation: 7 ERROR: duplicate key value violates unique constraint "image_tags_image_id_key" DETAIL: Key (image_id, tag_id)=(5800567, 661176) already exists.

Query: INSERT INTO image_tags(image_id, tag_id) VALUES (5800567, 661176), (5800567, 661176), (5800567, 926), (5800567, 678159), (5800567, 4486)

Args: array ( )

Version: 2.11.4 (on 8.2.26)

Stack Trace:

#0 /app/core/database.php(230): Shimmie2\Database->_execute()
#1 /app/core/imageboard/image.php(599): Shimmie2\Database->execute()
#2 /app/ext/post_tags/main.php(173): Shimmie2\Image->set_tags()
#3 /app/core/send_event.php(165): Shimmie2\PostTags->onTagSet()
#4 /app/ext/bulk_actions/main.php(289): Shimmie2\send_event()
#5 /app/ext/bulk_actions/main.php(149): Shimmie2\BulkActions->tag_items()
#6 /app/core/send_event.php(165): Shimmie2\BulkActions->onBulkAction()
#7 /app/ext/bulk_actions/main.php(186): Shimmie2\send_event()
#8 /app/core/send_event.php(165): Shimmie2\BulkActions->onPageRequest()
#9 /app/index.php(91): Shimmie2\send_event()
#10 {main}