Fabric v0.14.19
Backpacked v2.2.0
Minecraft v1.19.2

Certain settings in the backpacked-common.toml file keep resetting on launch. I'm trying to change the inventory size of the backpacks. The setting backpackInventorySizeColumns seems to consistently stay to what I set it as, but the other setting, backpackInventorySize, keeps resetting back to 1 as soon as I launch the game.

This is happening to me aswell, did you manage to find a sollution?

Happening here as well. I change the backpacked-common.toml file to 27 "backpackInventorySizeColumns", I save and close. Soon as I open it again, its reset to 9.

Also having this issue (backpacked-forge-1.20.1-2.2.5), and when the file is made immutable, the server crashes. Doesn't seem to crash when the file is readonly but the field still changes, so it's almost like the file is being recreated

Figured it out by looking through the code, the max backpackInventorySize is 7. It's not very obvious just from the config and unintuitive how it enforces the maximum. If you exceed 7 it will revert to default. This is probably the same for many other fields. For example the max columns is 13. See here, IntProperty.create 3rd argument

The configs work fine, the problem is that you've provided a value that is incorrect. I am however partly to blame since I don't specify in the config property's comments what the allowed values/range is. The maximum rows of a backpack is 7, while the maximum columns is 13.