Do Canadian Amex cards earn multipliers in the US?

Title pretty much says it all. I used my cobalt in Florida in September and was getting 5x at restaurants but heard that changed in October to just 1x. Did all Canadian Amex cards lose their multipliers? I have a trip to the US coming up and was considering getting the Gold card for the 2x travel but I might as well just use my Cobalt or Infinite Travel if I can only get 1x.