Hi Paul, I'm the code monkey here but I'll do my best to be user-friendly
First up, do you get better results if you consistently click the logo on the cards, or instead on the top or bottom well away from the logo? I seem to remember an issue with that a while back. Play a couple of rounds both ways, see if it makes a difference.
If where you click doesn't affect the result:
Nothing has changed on the site recently, and definitely not in the code for Pairplanes. While the game is in progress, there is no network traffic back and forth for your ISP or our hoster to mess with. That pretty much leaves some change or other on your side.
What web browser are you using, and what version?
Have you updated it lately - or has it updated itself automatically?
All the code runs in your browser, so this would be the first place I'd look. After that, it's likely to get a whole lot more esoteric.
My friend and I applied for airline jobs in Australia, but they didn't Qantas.