https://github.com/mongodb/mongo/blob/7578d0b8285c18fd0007bf78a2bbc49720fb2879/src/mongo/gotools/src/github.com/mongodb/mongo-tools/mongodump/oplog_dump.go#L119

2019-10-10T03:43:54.191+0200 checking if oplog entry 6745895563192959027 still exists
2019-10-10T03:43:54.191+0200 oldest oplog entry of timestamp 6745959210313318409 is older than 6745895563192959027
2019-10-10T03:43:54.192+0200 Mux finish
2019-10-10T03:43:54.362+0200 mux completed successfully
2019-10-10T03:43:54.363+0200 Failed: oplog overflow: mongodump was unable to capture all new oplog entries during execution

oldest oplog entry of timestamp 6745959210313318409 is older than 6745895563192959027

I believe this should say "newer" or the entries should be reversed.