I have seen this as well. One of the alts I have is inside of ARR patches and was assigned a ShB Raid, E6 to be exact. As this is an alt that I am not needing anything on, this is not a huge deal but newer players will have no chance to reach this unless they burn all of ARR through base ShB as far as MSQ requirements are concerned.

Additionally, I have heard that Free Trial Accounts can get assigned PvP, which is something they are unable to complete.