I find it actually funny, how this turned into a drama with it's own story. Something similar happend to me aswell, where my feeder wife suddenly was put under the gantry feeder by another feeder.
My wife was a Sneaky Feeder so it always was wholesome, while the other Feeder was a dominant Feeder. So in my story it was like, the dominant Feeder was so obsessed with me, that she started to eliminate the competition. So to protect my wife, I "sacrificed" my body by tricking the dominant Feeder into drinking the GOAT shake. Which immobilized her pretty quick, and before she got stuck in her home, I put her under a Gantry Feeder and filled it up with a ton of snacks.
Yeah she is stuck there now for a good month. >:D
But to the occurence of this situation is a bit unclear to me aswell. That a Feeder can put another Feeder under a Feeding System is one thing.
But a not Enormous or higher person, cannot fit under a Gantry Feeder by the rules of the game, so that part IS a bug.
Just out of curiosity, did you perchance Export and Import your file and moved it to other Systems?