Today's lesson is:
KEEP YOUR PLATES DRY.
This means, if your pressroom isn't completely weather-proof, don't store your plates in there, even for a few hours overnight.
It hasn't rained for a few weeks (Aussie droughts, sigh) so this hasn't really been an issue for me until today. It started raining during the night and hasn't stopped since. Most of my plates were tucked away, but the koi and dog plates (which I test printed yesterday afternoon) were left out on my desk. The very moist air got to them, and they curled up. The koi plate actually started breaking apart, so it's now useless.
I'm very disappointed, as I've really been looking forward to printing the koi. I always learn the hard way. Now I have to save up a bit of money to get them remade.