Collection increases in size when I try to sync?

[jcznk]

Some background info: Anki Desktop asked me to force a one way sync because of some database inconsistency or something similar.
(Earlier today, I synced my collection to AnkiDroid after a long time not using it.)
Since my collection size was above the limit, I deleted a bunch of stuff to bring it below 250 mb and down to about 240 mb.

However, when I try to sync it to AnkiWeb this message appears:

And the collection’s size changes to 260 mb:

Using “Check Database” brings it back to about 240 mb, but then the same problem arises every time I try to sync.

[dae]

Before a full upload, the collection is downgraded to an older version, and those changes increase the size.