HMDI issue.

[Patsy+2018]

I've noticed recently when I turn my glass tv off using the remote control it switches off but comes back on again.
I get a blue screen saying No signal detected on HDMI and telling me to visit Settings. The strange thing  is I don't seem to be able to access the HDMI inputs in Settings. This has only become a problem recently.

[CoffeeDrinker]

Do you have any other devices attached via HDMI? Sounds a little like another HDMI device is sending a CEC power on command (CEC = Consumer Electronic Control, a means of HDMI connected devices controlling one other. For example, a Blu Ray player remote control being able to adjust the volume of the TV it is connected to)

[Jporch316]

Definitely sounds like a connected device issue as post above by @CoffeeDrinker 

as a first port of call try pulling the plug for a few minutes in case it's a system glitch.