This depend which broker you have, when the clearing house is Canadian, it seem that everything are right and that no PDT is apply, some example that I know:
You can search on this forum about this topic, a lot of thread about this regulation that come from the SEC and hitting many trader.
Summary, if you trade on a margin account and that you have under 25kU$, you have a limitation of 3 daytrades (open and close a position in the same day) in 5 working day.