Saw this last night after noticing the way stairs work changed, went to post but someone fixed it before I got the chance, just went back this morning and the changes they made must of been reversed or something since it went back to this
ok so if you go up the stairs and back down it will display the correct version, but when you die and spawn in it will show as the image I posted above
edit: depending on which hole you drop from it appears differently
Let me know if it's fixed. Those aren't tile-errors exactly, they're overlays generated on the fly when you use the stairs.