Here's how the system handles path mappings.
On any given app, if there is a container path of /config, it doesn't matter what the template author puts into it as a host path by default. Unraid will always override the host path with whatever the setting is for default appdata path (Settings - Docker) and append the name of the app after it.
On any given app, if there are any paths pre-populated (other than /config) in the template, CA will automatically adjust them IF they directly refer to an array drive or a cache pool. It looks at the user's system, and if the template says "/mnt/cache/data" and there is no pool named "cache", it will change the path to be the next available cache pool (alphabetically). If the user has no cache pool at all, then it will change the path to be /mnt/disk1/data (assuming there is a disk 1, otherwise it will change it to disk 2 etc)
These changes only happen when installing a new template and are the default settings. If you're editing an existing app, then you can override the settings for /config all day long. (Or override the paths when installing a new app - these are the default paths the system offers up to the user.)
As an aside, technically on 6.9+ there should be zero reason to ever still have to use /mnt/cache/appdata/... instead of /mnt/user/appdata/... If the appdata share only exists on the cache-pool, the OS dereferences /mnt/user internally to instead be /mnt/cache/...
But, like everything else IF there are still problems with /mnt/user/appdata with certain applications, let Tom know.