Good day,

Jabba has a barrel upgrade called Void Upgrade. That should remove any excess items that flows into the barrel if it is full.
When used with sorting barrel, refined relocation sorting doesn't insert any items if barrel is full, it will just resort to other suitable location like chests that can pick up this item.
Example:
I have cobblestone sorting barrel with Void upgrade with 63x64 items. And 2 chests, 1 for input, 2 for cobblestone.
I put 64 cobblestone in chest and system sorts Cobblestone to Cobblestone barrel, and it now becomes 64x64 barrel.

I put 64 Cobblestone again and system sorts to Cobblestone chest instead of Cobblestone Barrel with Void Upgrade.

If I put 64 cobblestone to 64x64 Sorting Barrel with Void Upgrade - 64 Cobble stone just gets eaten, and Barrel is still 64x64.

I can provide screenshots of the issue if needed.

Best Regards, DeForce

Found that it's fixed. Sorry for creating issue.