I'm wondering if the pink disappears AFTER you wash a load but reappears, over a number of days, as you're refilling the dishwasher w/dirty dishes. (In my house, we run it every 4-5 days ...)
Anyways, if what I described is happening in your case, the pink could be Mold. One way to test this is to lightly rub the pink with a mixture of household Bleach that's ratioed 1 cup to 1 quart of water. (Cut in half for smaller portions ...) If the pink disappears, it's most likely Mold.
Mold/Mildew will form in damp, moist, warm conditions. The dishwasher is a VERY good 'home' for M/M. Let me know if this is the situation and so on. For now, my best to ya and hope this helps.
Jay J -Moderator
PS: We don't have an M/M 'problem' in our dishwasher. We empty right away and let it dry out ...