Hi, I have the same problem with my Rainbow Spring not working - I have tried all the 'fixes' and am playing with latest version of game and ios. I updated to version 2.6.3 on Jan 20th. My rainbow spring stopped working today sometime.
Please help! I'm not going to win a Unicorn (or even ever manage enough trophies for a foal) but I would like to hold onto 5th or 6th spot!