Why did the hotel lights suddenly switch on and off?

According to your description, the hotel lights will suddenly switch on and off, because you didn't describe it clearly, there may be two situations:

The first one is because of the voice control light. The sensed sound will automatically light up, and it will automatically go out after dozens of seconds.

The second is because of circuit problems, such as unstable voltage or intermittent current caused by poor switch contact.

You can talk to the front desk of the hotel and ask them to check.

Good luck, please accept it if you are satisfied.