Survivors not using stairs

[meuqsaco]

Any idea why my survivors won't use these stairs in the picture? They just ignoring it as if it doesn't exist.

https://imgur.com/a/akw98eT

[Flin Fredstone]

i don't know. But make the stairs one tile instead of two. See if that changes the behavior ?

[NickTwist]

Is there a wall there? - I do not see a doorway frame on top of the stairs.

[Malicite]

Try Flin's idea, if that doesn't work, take out the first block in the room and turn it into a step block.

*Edited* There is a guide on how to build multi layered floors.