In Community episode S03E19 Curriculum Unavailable, when the study group is talking about what a crazy year they have had, they show an incident in which Troy slams his hand against the table.(This incident could not have happened after they were expelled, for obvious reasons)
This happened 2 months after they were expelled(according to Shirley's words at the start of the episode)
After they finish telling the Doctor about these incidents we see that Britta squeezes Troy's hand and he cries out in pain.
Now, I guess there has been a mistake because I think even a broken hand will be repaired in two months So is there a problem with the Community Timeline?