The FileMove() function has a difference in behaviour between Lucee and Adobe ColdFusion and Windows O/S.
When the file has the READ-ONLY attribute set, in Lucee it is not possible to move the file as it throws an exception. Windows and Adobe CF both allow the file move in the same circumstance.
The intention of the READ-ONLY attribute is that you cannot write to or modify the file, but should not prevent a move of the file's location.
I believe the issue is in FileTag.java on line 484 - it should not be performing the check on source.isWriteable().
I've added a test case, fix for this ticket & confirmed the issue happened on lucee. We can't able to move the file from source to destination with a read-only mode. ACF works as expected. , you are right the attribute doesn't a matter for the action move for a file.
Pull request: https://github.com/lucee/Lucee/pull/705