This problem was happening occasionally with Pan F. I just developed a roll the other day that had a slight pinkish cast. Since we had an overcast day yesterday I taped the archival sheet to the window. After about 8 hours of indirect light compounded by filtering thru a fairly heavy overcast, there was little change. Then the sun broke thru with some dappled light and was at an angle to directly hit the film. In about five minutes the pink was completely gone. Another roll was developed several weeks ago and has just been sitting on the table. I checked it and it has cleared, as well.