How often do custom m3us get reloaded on server reboot?

my server just updated, and the frontend (i use my channel mapper that loads the custom m3u from my backend) couldn't find any channels, i'm guessing because they both updated at the same time and the backend hadn't loaded yet when the frontend came back up. this means that the m3us all showed zero channels, and nothing was recording.

is there a way around this? how often does the channel re-check to make sure it's loading a playlist that is showing zero channels?