Exceed amounts in bonus checks are sometimes factored by the other taxes calculated, Tiffany56. I'm here to explain this topic further.
In QuickBooks Online (QBO), when you calculate the bonus As net pay amount, you'll need to pay taxes in addition to the sum you enter for your employee to receive the total $ 1,000. The Preview payroll details tab helps review the counted taxes after running payroll. You can refer to this screenshot to locate it:

Moreover, I also recommend checking your other employees' setup to see if your employee with the expected bonus amount has a different tax setup that might be causing the difference.
Furthermore, you can always refer to this article as guidance when configuring your employee bonuses: Pay employee bonuses.
Additionally, you can run payroll reports for business insights by selecting Reports from the left menu and entering a report name in the Search box. You can visit this material for a list of available payroll reports: Running Payroll Reports.
Lastly, if you need further help handling your payroll, you can Explore QuickBooks Payroll to streamline your payroll process.
Your financial accuracy with QBO payroll bonuses is our top priority, and I'm here to support you every step of the way. If you need further clarification or assistance, return to this thread and tag my name in the comments below.