NightBot is listed as a moderator on my channel for a long time now and has been working fine.
For the past week, NightBot has is leaving my live stream randomly and I had to go to Dashboard and ask it to join again. This behavior recurs every few hours.
Nightbot was running out of its YouTube API quota daily until a couple days ago (when we were given more), which caused it to leave channels. This is probably related to that happening.