I've just upgraded to GMS 2.0 on SLES11SP3, hoping this problem would rectify itself, sadly it hasn't.
I administer a network with GW2012 (on OES11SP1) and DataSync (now GMS 2.0). We have about 50 users who are happily syncing various devices.
Sometime ago, I noticed that one particular folder in my Cabinet was not syncing. Unfortunately, it's where the majority of my inbound mail is filtered into. I have removed myself from the Group we use for GMS 'membership', then re-added. I have run database repairs, followed TIDs to remove myself from GMS completely. I have run GWChecks on my mailbox and the PO. But today I still have nothing in my folder.
There is no error, it just spins a refresh on the phone (GalaxyS4, 4.3) and remains empty.

Has anyone seen this? Any ideas?