Strange Behavior of a young starter

Okay so i mixed up a starter with KA White whole wheat and pineapple juice. I let it sit for 2 days at around 69-72 degrees. I ran out of whole wheat and fed the starter some whole grain rye flour by Hodgson Mill, and within a few hours (4) it doubled. The starter before the feed rye showed no signs of life. Is this normal? Is there something in the rye i should be aware of?

SndBrian