Operate releases
Relavent operate code

In a nutshell those pipes take items and remove them immediatly.
i probably should be waiting a tick, still create should probably not set the slot five times or maybe check if the item got removed.

Reproduction Steps

1. Place down a operate entrance pipe
2. Place a chute above it
3. put item in chute

Mod Version

0.5.1d

Minecraft Version

1.20.1

These pipes have complex logic that's incompatible with fabric's best-effort transfer API inventory wrapper. There's nothing that can be done on Create's end.
You'll have to move away from Inventory/SidedInventory and register a provider to ItemStorage.SIDED.