You notice a build up of .dat files in the following locations with Application Learning disabled at both the Site and Group level.
C:\Program Files (x86)\Symantec\Symantec Endpoint Protection Manager\data\inbox\learnedapp\computerapp
C:\Program Files (x86)\Symantec\Symantec Endpoint Protection Manager\data\inbox\learnedapp\apps
With Application learning disabled at the group and site level a smaller set of data will continue to be uploaded. This smaller set of data is related to threat detection data and is required by the Symantec Endpoint Protection Manager (SEPM).
This issue is fixed in Symantec Endpoint Protection 14.2 MP1. For information on how to obtain the latest build of Symantec Endpoint Protection, see Download the latest version of Symantec Endpoint Protection.