One more question - if this is cracked and moisture gets underneath it, is it likely window damage will result? I've got one that's impossible to reach without a tall ladder. If the only concern is cosmetic, I may leave it for now. Thanks!
This is an exterior glazing strip, so it does keep the weather off the end of the glass that is sealed. That said, it's not water proof. There should be drainage built in the frame to keep the water moving off the seal and not puddle.