Used muffin tray, cupcake paper at 150 degrees Celsius for 50 mins, bottom half different color to top half, quiches cooked at 180 degrees Celsius for 25 mins were even worse . What is cause
Was there spinach or anything in the quiche? Could have been caused by heavier bits falling to the bottom of the tin.
Also, 50 minutes seems like a lot for quiches; it's possible that they overbaked and something happened to the eggs as a result--overcooking does all sorts of weird things to egg protein. Try taking them out of the oven when they just barely jiggle in the middle!