I’ve been a member for a long time. Issue just came up today. My dad first noticed it on his phone (also Public Mobile) so I tested with mine. We are in Burnaby.
Mystery solved. My dad's phone was set to Do Not Disturb when phone is locked. That's why it "seemed" like sometimes phone calls would come through but most of the time they didnt. Hope this helps someone.
Took me an hour to finally figure out this was the reason I wasn't getting texts for 2-factor authentication. What a pain. Thanks for logging this. I've emailed a mod.