Temp log gap when doing log query

We have loki v2.9.1, and we see multiple cases, when we do the query, there is a gap. and the log is already been ingested. because from the query in the snapshot.
but there is always a gap, and moving with times.

we use Ceph as storage layer. any idea?

What do your loki configuration and infrarstructure look like? Do you run a cluster of nodes for Loki, or single node?

a cluster

Can you share your Loki configuration please?

could you specific for which part?

All of it. Exclude any secret of course, if there is any.