Resolved No hot water. Frozen pipe??

[jdlong49]

It has gotten pretty cold today and dropped to low 20's and I am suddenly(working normally earlier this evening) getting no hot water to the shower or bathroom sink in my 2022 Transcend 200MK. I am still getting hot water to the kitchen sink and cold water to both sinks and the shower. The lines from the water heater to the bathroom are inside (I believe)so I don't think they are frozen. The oddest part is if I open both the hot water in the sink and shower, and then open the cold in the shower, cold water will come out of the sink. I let it run for a while and it is straight cold, never gets hot. So something is rerouting cold water to the sink when both hot and cold are open in the shower. I can't figure out where the issue is because I have no diagram of the lines. Anyone have any idea what this may be and how to remedy it?

 

[TheLooks]

Cold water is passing thru the faucet. Many times they warn about leaving the outside shower in the on position and turning the flow off with the button on the spray head. This allows cold to travel to the hot side and can make the water warm, not hot. You have a blockage and I would suggest getting heat into any areas that are closed off that you can.

 

[jdlong49]

UPDATE

The issue self-corrected after 2 days. Everything is working normally. I have no clue what caused it, maybe it was frozen somewhere but it got even colder the night after it started working again and hasn't done it since. Guess it's one for Unsolved Mysteries.