Hello @jdthorn
The problem that you are having may be related to this issue: Lock the drive to prevent failure on verification · Issue #3197 · balena-io/etcher · GitHub
Please take a look at this forum post to see whether it helps you: Flash failed on umbrel-os-v0.3.8
I tried flashing Umbrel v0.3.8 on Windows 10 and although the verification failed for me too the card had been successfully flashed. It might be worth you trying the card anyway. See my comments in the forum post I mentioned above.