The error for the offset adjust is from using the Payroll Item. The adjustment should have been entered on the Expenses tab. You can Fix that check any time.
The point is, you want to show you are "paying" what is accrued, but Adjusting it for a rounding drift on the Expenses tab. Adjusting the item, means you under- or over-paid that Item, which was not the intent.
When you have a Credit with the agency, or when you owe an additional fee or penalty, and you want to Adjust the Check from gross to net, make the adjustment on the Expenses tab and do not affect the payroll item(s).