I had this once I had a pop up come up on the screen advising that maintenance is due to take place in 30 minutes, then had another one come up for 20 minutes and again for 10 minutes. Gives times to change over to another device if playing longer game etc. I’m not sure if something has changed but I did not have it constantly and liked being reminded at the 10 minute intervals as sometimes easy to forget if contemplating a difficult position on the board .
I think the series is 3 warnings - and I know if the warning does not apply to you it is annoying, but for the people just starting up the board and entering a rated game - we have to send the series.
These events are pretty rare, so it is not something you will see very often.