Andrew, does it look like the buyer is a registered PayPal user - does he/she have previous transactions through PayPal?
The reason I ask is that PayPal does not require people to actually register when paying by CC and I'm wondering if that is where the problems are coming from. I've encountered the same difficulty with other provinces and it seems the buyers ability to type in their province (rather than from a menu) has messed up a variety of things including applicable taxes payable. I'm just wondering if this is an issue that PayPal needs to address or, as you say, just a temporary glitch.
Bill