I just started testing caching mode (GW2014.2.1) and am finding that item status (read,delete,etc.) changes made via GMS (14.2.1) do not synchronize back to the client in caching mode. They do synchronize to the online mailbox. Synchronization works fine for the other direction.
Gwcheck has been run on all databases and I've manually retrieved entire mailbox to refresh the client in caching mode.