Bug with Osiris

I have a bug with Osiris. I'm almost at the end of my quest, but now I'm asked to be funny with Osiris. Except that the only interaction I can do with him in the funny bubble is "be examined". But nothing happens. Also, I'm told in the description of the quest to make "a joke by farting". Except that this interaction does not appear in the "funny" bubble. So I find myself stuck and since it's a progression quest, I would like to finish it.