What's the temp outside where your hose is laying?
more than likely you are just getting the warm water that has been sitting in the hose.
Happened to me for 2 weeks straight ending last week. Temps were either near 100 or 100+. 150' of hose laying on the ground in direct sun. Took 5 minutes to get to the cold water. Ended up leaving grey water gate open during family shower time. Not really sure how to avoid it, but in the end, wasn't that big of a deal.