Labels filter values for loki in grafana disappearing for older logs

[samyakkali]

I have older logs which are not modified for long time stored in loki 3.0 promtail 3.0 helm charts. I can see them for first 15-30 min in grafana loki (once loki and promtail are started) page in label filter values and then they disappear from label filters values , if the logs are not updated regularly. I really appreciate if someone can help me if this is an configuration issue or what’s the workaround .Logs are on mounted volumes.