I think there has been a mistake in the patch note description, as the handgun uses the same damage profile on aimed and unaimed shots, so the damage increase vs armour has been bumped from 1.0 to 1.2 on both attacks.
The shots not piercing shields however was a bug and has been fixed internally. Will be in a patch soon.

Thanks for the report! I had fixed a similar issue that didn’t have time to get merged for the release.
The fix should be included in a patch soon.