IB enforces the patterned day trader rule $25K for trading U.S. Equities and not Canadian Equities. This rule has nothing to do with day trading Canadian Equities and unfortunately is a disadvantage to many who want to trade U.S. Equities with an account under $25K U.S. IB is just playing by the rules handed own by the U.S. Govt. Shit Happens goofy govt. rules.
They should remove the PDT rule, it will help brokers earn more money. IMO they should tighten the screws after long periods of market advancements, and loosen the rules after the market has been cut in half. But they don't, they do just the opposite of common since.
Yes, you can day trade in an IRA within the PDT rules. You just can't buy stock on margin or short stock.