Playing Sky Factory 5, and a recent update to Sophisticated Storage has allowed the Storage Controller to accept items that it does not have a place for, and then voiding them, I guess? (I haven't found where they've gone, and there's no feasible place for them to go, so assuming they've been voided.)

Above is my setup, where the barrel acts as a filter and an overflow. It was previously about a quarter of the way full of overflow, and all that was voided off. Underneath the barrel is a LaserIO node, which typically only allows items to go through it if there is space on the receiving end for the item to go, i.e, no internal inventory. Replacing the node with an item cable from Cyclic (has an internal inventory) does not fix the issue, and still allows the item to go into the storage controller, and then be voided off.

Thanks for reporting this. I am not 100% that is your issue because I can't see the setup fully, but I am guessing you have at least one locked limited barrel in that wall with empty slot and I just found a bug with that was causing these limited barrels to void items that can't fit in these slots. Just pushed a fix for the bug and should be up on CF / Modrinth in a few mins

Yeah, the wall of barrels are all locked so it's probably the same bug. Thank you!

ok, I am closing this now, but in case the update wouldn't help you feel free to reopen, I would just need more details on the exact setup if that happens to be the case.