I'm gathering bandwidth data of some servers using prometheus federation and grafana for monitoring. Last week I noticed that something weird happened to my grafana dashboard, seems garafan can't have access to data before specific time, I thought my server reseted somehow, but using "docker ps" I notices my prometheus container was up in past couple weeks, this thing happened one more time after 3 days! I didn't have this issue in past. I couldn't find out what's the problem, and don't know how to troubleshoot this issue. I also thought that prometheus volume is reseted, but when I checked the prometheus volume folder, noticed that old data are still there!