Hello 'pauline',
<Canadian exchange rate not up to date>>
Hmmm, not sure what you mean by that exactly, but as exchange rates fluctuate all the time, perhaps ebay does not keep up minute by minute. The following is a link I like to give me a rough idea of where our sickly loonie is from one day to the next:
https://ca.finance.yahoo.com/currencies/converter/#from=USD;to=CAD;amt=1
If you mean that the Canadian dollar "equivalent" you see on USD listings is less than what you really pay at the checkout, then yes, it is always like that. The estimate is always friendlier than what really comes off your card or account.
I'm afraid there is nothing for it but to accept that is how it is. The difference isn't much, though, depending on the original costs. Just work out the extra in your head and add it on when contemplating a purchase.