I’ve managed to replicate this problem.
The problem is that --cache-db-path and --cache-chunk-path are using the default value of --cache-dir not the value of --cache-dir set on the command line.
This is due to the initialisation sequence of rclone… It is fixable though. Can you please make a new issue on github about it and we’ll fix it 
While researching this, I realised there is a work-around. You can set XDG_CACHE_HOME to set the default value of --cache-dir