TL;DR: They're not being allowed in. If they slip through the cracks somehow and you get some, then awesome.
I've spoken with someone who deals with the actual importation of these products within the CBSA and they've told me they're basically not being allowed in.
They're incorrectly blocked to 10 rounds by just adding springs to the bottom instead of a permanent block, pin or rivet that it should have.
They're also originally USGI 30 round magazines spray painted over the original stamp and marked as LAR magazines and sometimes incorrectly as "10x 55.6mm cartridges". Yes, "55.6". They need to be manufactured as a LAR magazine so this is an issue.
The documents they say they have for them are just a copy of our laws which only shows that they know they're pinning them incorrectly and knowingly breaking them.
Zahal isn't shipping any more orders until something happens to the shipment being held by customs.
If you've ordered some, they are offering refunds, so you can get your money back if you like.