Yes, this is a common issue and it’s not the Canadian address itself that causes the problem, but the USPTO rule that foreign applicants must be represented by a US-licensed trademark attorney when filing a US trademark.
If your application was filed directly or through a non-US firm without a US attorney of record, the USPTO will refuse or stall the application, which then leads to Amazon Brand Registry rejecting it. Many sellers in Canada successfully register US trademarks, but they do so through a US trademark attorney who can act on their behalf, even though the business address remains Canadian.
I would check the USPTO application to see whether a US attorney is listed and whether there are any outstanding office actions, then either have the filing corrected or refile properly with a US attorney, after which Brand Registry approval usually goes through without issues.