Here's the screenshot.
My colonist is going to realx inside an enemy building with a chair/table.
https://www.reddit.com/r/RimWorld/comments/6dns5s/a17_my_colonist_wants_to_relax_inside_enemy_base/
What a cheeky b'stard!
Although definitely a bug, thanks for reporting (and that's some nice efficiency skills you have there, managing to capture two bugs in one screenshot like you did. How are your crafting skills btw? As it looks like you'd make a fine colonist :D )
Should be fixed in A17b or A18. Thanks!