It depends. It can be elevated for a while after exercise I think. I went for a ride earlier (got back at midday) where I avg 150bpm for 90 mins, and it's still sitting about 10bpm higher than usual resting now.
Yeah think its not that uncommon. doesnt take too much to get to 100 (for normal people), Also depends on fitness / difficulty of the ride - I'll often be there or higher for a while after a tough one.