It seems like they are related issues, the same code on the same machine runs differently on different runs getting different errors. I can try to get the illegal memory access error with a backtrace though.
The 0% GPU utilization issue doesn’t seem like data loading. The CPU runs at the beginning doing data loading, then it trains for 100 iterations in 300s, trains for another 100 iterations in 300s, then GPU utilization goes to 0% and no progress is made for 45 minutes. I can try leaving it running longer to make sure this isn’t an intentional part of OpenNMT training but the timing makes this seem like a bug.