Characters wont rest on bottom floor, but jail, stairs and accessories will

Describe the Bug
I am creating space pirate ship and designing from bottom up. I tried to add characters onto it to make sure it was all good, but they don’t touch the ground the sort of hover a section above, so there is a cat just floating in air in the jail,

also, how would want walk into a room or jail cell if they were actually walking on the floor?

https://clips.twitch.tv/OriginalSlickStarSoBayed-6g7_PzSW6Pr8Jwt6