corner room

I AM playing a modded game but I am confident that this is not related to mods. The baby keeps going to the corner room which prevents me from shrinking the room (All vanilla features in 1.6 I believe)

When I try to build a corner room it wont allow me and it just says “Remove all items from the renovation area.” I’ve removed a lot of furniture from the room but it’s still not good enough. this is single player, English, Nintendo switch version 1.5.4 The only thing I could think may be the...