That seems like hundreds of hours? I haven't got too far yet so idk if you get a lot more later on.
Edit: Or does it just happen when it goes over 2?
When the bottom row goes over 2 and you click on the card, the extra spills over onto the next page (e.g. extra bottom-row dogs give more cat cards), but there must be something broken there. I've finally got time to look into the reported bug...
And yeah, to get that many cards is a crazy number of games played!