The problem I sometimes have is receiving nonsense pings at random intervals.
If you enter a room used by bots for testing stuff, the bots cease their opportunity to test their functionality. One of the bots pings members of the room. You (deliberately?) entered the room, so you get then pings. Maybe ask the bot-owner if you can opt-out of that, you can assist with testing once pushed ;)
Is it ever appropriate to flag chatbot pings as spam.
Never. Don't bring more work to moderators due to some test with a bot failing. If the bot is abusive in a normal operation, then it can be handled as any inappropriate message.
how long after you stop being active?
After you pressed the leave link you will be pingable for seven days. Just wait it out but don't enter that room again because then another 7 days of pings is waiting for you.
You can determine if you're pingable by running this in the Developer Console of your webbrowser:
console.log(d[i] + ' ' + new Date(d[i]*1000).toString() );
Where you have to change the url to the chatserver you're on and 721 to the room number you're interested in