It likely is-I used to work for CBSA (Combined Customs and Immigration); we would always get a list of the wrestlers coming in to do tours or TV. Quite a few needed a TRP (Temporary Residence Permit) to get in. I assume that, having done this before, someone forgot Killing's TRP paperwork, and the officers had to send him home.
FWIW, "Detained" in this case, usually means waiting around in the office before your return flight home.