Pipe pistons break shulker boxes (although 1 transfer gets through beforehand), and MC1202 (Container Dispenser), at the very least, doesn't pull from shulker boxes. I didn't test other ICs.

Yeah this is really an issue, but for the time being a workaround would look like this:

Even though the observer clock and the Pipe input piston are not connected, the repeater fools the plugin into thinking they are somehow.