I have a raspberry pi 4 with raspbian buster installed. I set the hostname using raspi-config to "myrpi". I can connect to it using ssh and it works fine. But after a few hours or so, the hostname changes to "myrpi-3" where 3 can be any number. The greatest number I got so far was 13. I know it changes because I scan my network using Advanced IP Scanner and it still shows the same IP address. I have no idea what is happening. I am running a mqtt broker, a postgresql database and a web server using docker.
I fix this by rebooting and it goes back to "myrpi" but after few hours, it changes to another hostname, example "myrpi-5".
Anyone experienced this before or knows what is happening and how to prevent the frequent change in hostname?
Thank you very much.