Set cache to "only", then run mover while docker / VM service is stopped
That will not do anything as mover ignores shares which are set to ‘Only’.
I suspect the current issue is that due to earlier activity some files exist on both the cache and the array. Mover will not overwrite an existing file. Such a situation needs to be cleaned up manually and it is up to the user to decide whether the copy on the cache or the copy on the array is the one to keep/