I would try adding a little water to just enough to test a screen.
CCI lists a shelf life of 30 days on coated screens.
Many of us have found these figures on similar photopolymer emulsions to be very conservative. Most brands list one year on sealed SBQ and CCI says "unopened", but once again, stored in good conditions, this can be fudged.
You, however, have apparently discovered one possible result of prolonged storage
