When I opened the backpack it didn't show the regular inventory layout.
There were no blue or brown slots, just plain gray like it was the regular inventory.
However, the bucket and tool slots worked just fine, even the bed.
I don't know what caused it, I just crafted the backpack and it appeared like that.
Modrinth (Fabric) mod version 1.20.4-9.4.3
When I opened the backpack it didn't show the regular inventory layout. There were no blue or brown slots, just plain gray like it was the regular inventory. However, the bucket and tool slots worked just fine, even the bed.
I don't know what caused it, I just crafted the backpack and it appeared like that.