SSR 2013 Agent is holding a connection open on a CIFS share

From our SSR management server I'm creating jobs that schedule backups for quite a few servers (about 50) in the same domain.  I'm pointing their backups to a CIFS share on another storage unit, but that storage unit accepts only 32 connections at a time.

Once 32 machine connect to that share to perform their SSR backup, none of them releases their connection -- even after their backups are completed.

Is there a way to make them release their connection?

All the servers being backed up are either 2008 R2 or Server 2012 (mostly R2).