Question: my iCal has changed a reminder from green to purple. I change it back, but purple returns. This has not happened before...

My 'personal' reminder color of green has been green since day one. Suddenly it changed to purple, and I cannot make it change back for more than 30 seconds--it will change to green after going to edit, get info, then return to purple immediately

by itself. A small circle shows up like something is downloading, and green becomes purple again. Very frustrating.