It's possible that you are hunting a site/sites that just don't have much.
And as Joel said, modern Canadian clad can sound crappy.
FYI, Canadian nickels, dimes and quarters minted since 2000 are steelcore with a nickle plating. Canadian pennies minted since 2000 are either steelcore or zinc core with a copper plating. Prior to 2000, our clad and pennies are similar to the U.S. coins and should read out just fine. You should have no issues with Loonies or Toonies as they are not steel. Often, shallow large coins will overload and make you think it's a big chunk of metal, so I lift up my coil a couple of inches and recheck to see if the target narrows down and resolves to an ID. Get a lot quarters, $1, $2 coins that way.
I hunt primarily in standard Relic mode, DISC around 2.5, and gain turned up until machine becomes erratic and then backed off until stable. My usual coil is the 10"DD. What I have found over the past few years, is that the MXT is pretty good at locking on and ID'ing iron, like nails, nuts, washers, etc. It's also really good at locking onto aluminum, gold, brass, silver, copper, etc. But on our nickle plated 2000+ crapola clad, the MXT is all over the place. THIS is the clue to getting more Canadian clad. When I get a signal that "sputters", does not lock on, ID's inconsistently with each pass and direction of swing from iron on up to silver, more often than not, it's a modern Canadian clad. I've found very few clad that locked on as a solid iron ID, unless it was already so corroded that most of the nickle plating was gone and unreadable, basically a slug.