Thanks Johnnie. When I look at the logs, I see an additional error "print_req_error: critical target error, dev nvme0n1, sector 123..." which doesn't sound good for a brand new drive.
In the meantime, I'll order a different drive, and make sure appdata is being backed up nightly. I guess that's what I get for trying to save a few bucks.
edit update 10/10/18: I grabbed a Samsung 970, and it's been working as expected the past 2 days. No errors during the TRIM operation.