The LogFileCollector class is responsible for gathering logs and in DBZ-8144, we added a check to make sure that we had logs with the given SCN based on the redo thread's recent checkpoint.

The problem is that during a log switch immediately followed by a checkpoint, the redo thread will report a checkpoint SCN after the read position; however, the log list may be missing the actual log containing the read SCN. In this scenario, the log list isn't consulted and the thread is seen as consistent when in-fact it isn't yet completely consistent.