In reply to Sustrak:
Without seeing the entire environment, it’s difficult to determine the exact issue. The get_next_item() call is blocking, so there may be something in the sequence that has a time delay or different block that waits until the same time slice as your vif. When the sequence_item is sent to the driver, the simulation is at time 320000, but the vif clocking block hasn’t been processed yet. You then wait for the vif clocking block (at the same time), which then occurs in the same time slice, hence the same simulation time displayed.
Look at the sequence and make sure that it is untimed or doesn’t have a different blocking mechanism.