The current test code relies on the clusterTime returned by the insert command to be same as the time stamp written to the oplog. It looks like the clusterTime returned by the insert command is ahead of what is written in the oplog which is causing the test failure. Based on the oplog entires, it looks like there was a refresh on the collection.config.cache collection which incremented the clusterTime.

To fix this, we should read the time stamp from the oplog, instead of relying on the output of the insert command.