I had an instant win fuel card on my second play of the day a few days ago. I usually only play once, but if I have time I'll have a few goes. Never had any issues with freezing, I play on Firefox. I usually answer a question wrong on purpose to avoid going down a "snake" to finish the game a bit quicker. Instant win was about the second line from the top, so it isn't just ladders that it can happen on, it's anywhere.
Good luck and keep trying, not long until it finishes.