Not sure if this is a bug or not

I've been playing Tahm Kench a lot recently and noticed that sometimes when I eat monsters and spit them against a wall they go through the wall. My cursor is in front of the wall and when I spit them out they fly over the wall and proceed to lose their new "patience" bar and then reset. I'm fairly new to Tahm so I'm not sure if this is something that just happens, but I thought they were supposed to hit the wall when i spit them out. So far it's only happened with Gromp and Scuttle