[advice] How to keep cat out of chipfeeder

Earlier this year, we adopted Loki to keep our Bast company after Ferrix died last year.

Bast and Ferrix both were fed on schedule, several times per day. Ferrix sometimes left some food for later, but Bast is a vacuum so we would take the leftovers away to be given later when he came asking.

Loki, however, is a grazer - he'll eat some and come back multiple times over the course of the day. Thus we got a chip feeder, so we didn't have to take it away all the time.

Bast soon figured out that he could eat from the side when Loki was eating as well, so we added a side barrier. This worked well for a while, but mister smarty-pants has now figured out that it takes a few seconds for the lid to close after Loki wanders off, and that if he sticks his head in fast enough, the lid will bounce off his thick skull, back off and stay open... At first it happened very occasionally - presumably he doesn't like being hit by the lid - but it's happening more frequently, indicating that he's learned that tolerating a bump on the head means more food.

Does anyone have similar experiences and knows of ways to stop that behavior? We've considered trying to move Loki to scheduled feeding as well, but we're not willing to start until he's off the kitten feed, because the volume is notably bigger than regular food.

Attaching a picture of both for reference 🙂