When a file is created, renamed, or deleted, the new name of the file is reflected in the file system entry on disk only when the containing directory's metadata is flushed to disk. If the system crashes before the metadata is flushed to disk, the data for the file might exist on disk, but there is no guarantee that the file system contains an entry for the newly created, renamed, or deleted file. In a test case we noticed that after a system power loss a transaction log containing valid log entries still had the name of the transaction log template file.
In release V11 and later, c-tree ensures that creates, renames, and deletes of transaction log files and transaction-dependent files are followed by flushing of the containing directory's metadata to disk. This change also applies to other important files such as CTSTATUS.FCS, the master key password verification file, and files created during file compact operations (even if not transaction dependent).
To revert to the old behavior, add COMPATIBILITY NO_FLUSH_DIR to ctsrvr.cfg.