Saving a file fails in Windows 10 in a particular (not known) circumstance

When Jalview saves a file it produces the below exception with a '"issue with backup file. Continue anyway?" or somesuch dialog'
[ probably: label.backupfiles_confirm_save_file_backupfiles_roll_wrong + label.backupfiles_confirm_save_new_saved_file_not_ok + label.continue_operation found in BackupFiles.rollBackupsAndRenameTempFile() ]

When saving again straight away the save succeeds.

In the reported case, the file is on a non-main letter drive (E:) and the error happens when the application is installed on either C: or E: drive, although it is not clear if this is necessarily connected. The different drive is an internal HDD not network.

This happens consistently (for the user) whether Backupfiles is enabled or disabled.

See comment https://issues.jalview.org/browse/JAL-3628?focusedCommentId=23910&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-23910

The exception is (full DEBUG in attachments)
java.nio.file.FileSystemException: E:\PATH.fa: The process cannot access the file because it is being used by another process.

   at sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:86)
   at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:97)
   at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:102)
   at sun.nio.fs.WindowsFileCopy.move(WindowsFileCopy.java:376)
   at sun.nio.fs.WindowsFileSystemProvider.move(WindowsFileSystemProvider.java:287)
   at java.nio.file.Files.move(Files.java:1395)
   at jalview.io.BackupFiles.moveFileToFile(BackupFiles.java:908)