Running Software (issues missing this information will be deleted):

• Addon version: 9.1.3
• Server patch: WoW Version 9.1.0.40725 (Retail)

Have you read the changelog? (please don't waste our time)
Yes

Describe the bug
The Addon ignores the standard bag "Backpack" when adding items and when sorting items. The first 20 spaces (standard backpack) only get used once all other non-ignored bags are full.
This happened first on one of my Alt chars and since then started spreading to all my other chars. I have already twice removed the addon, purged the WTF folder and re-installed the addon and nothing changed.

To Reproduce
Steps to reproduce the behaviour:

1. open inventory and click sort. i made a video, link below.

Expected behaviour
Items should get sorted and inserted into the Backpack first.

Screenshots
video (gif): https://gfycat.com/happygoluckypointedhairstreakbutterfly

Error Logs
None

Additional context
Nothing