Both these places change the masher user. Sync them up so they do the same thing instead of changing back and forth each run.

roles/atomic-composer/tasks/main.yml

@@ -5,7 +5,7 @@
 
 - user: name=masher
         shell=/bin/bash
-        groups="mock,fedmsg"
+        groups="mock,ftpsync,fedmsg"
   register: user
 
 - file: path=/srv/fedora-atomic/

roles/releng/tasks/main.yml

@@ -23,7 +23,7 @@
   group: name=masher gid=751 system=yes state=present
 # masher user 751
 - name: add masher user as 751 - and group
-  user: name=masher uid=751 group=masher home=/home/masher groups=mock,ftpsync
+  user: name=masher uid=751 group=masher home=/home/masher groups=mock,ftpsync,fedmsg
 # masher ssh keys and config
 - name: add masher ssh dir
   file: state=directory path=/home/masher/.ssh mode=700 owner=masher group=masher