No node is down for months. And yes, I am surprised to look at Unix timestamp on files.
system.hints is not used in Cassandra 3. Can't explain the files though, are you referring to the files timestamp or the Unix timestamp in the file name? Is there a node that's been down for several months?
I observed a strange behavior about stored hints.
Time stamp of hints file shows several months old. I deleted them and saw new hints files created with same old date. Why is that?
Also, I see hints files on disk but if I query system.hints table, it shows 0 rows. Why system.hints is not populated?