iCloud backup suddenly went from 500MB to 2,5GB

Hi,

basically the title.

Yesterday evening I received an alert that my iCloud space was almost full (I only have the free 5GB), yet I hadn’t downloaded any new apps or created any more content in the existing ones than before, nor taken a lot of photos.

I checked into Settings>My iCloud >backup details and the MBs of apps in the backup do not add up to 2,5GB.

I have iCloud Photo Library active, and that shows up separately in my iCloud.

I deleted the backup, rebooted the phone and created a new backup, but I still get the same alert about iCloud being almost full.

Is this a bug?

Is this a consequence of the issues iCloud had a couple days ago?

anyone else had this same problem and how did they solve it?