Why would the site change from the .ca (Canadian) to the .com while making a purchase and then ask me to sign in again?

[i.am.canuck]

So, i was checking some of my old sellers from 2004 from some of my early feedback and went to make a purchase. The site asked me to sign in again and noticed i was no longer in eBay.ca, but instead eBay.com. I have talked to eBay about this once before and the person said that he has never heard of this.