OpenVPN stops at 1gb

[spamcram]

I have openVPN connected working fine. But when Bytes Rcvd under "Status>OpenVPN" reaches 1GB, it stops any more data coming down (and cuts off all clients), until I restart the service which resets the counter to 0 and works fine until reaching the 1GB again.

I don't have traffic shaping enabled, nor any bandwidth limiting. What is wrong with this? On version 2.2.4.

dual core 2ghz, 2gb ram, 80gb hdd.. hardly using any resources.