Yes, the payments I made were calculated by TT to avoid any tax penalty regardless of how much I owed at tax time. However, since I didn't pay the 4Q payment, the safe harbor provision of paying more than my previous year's tax wouldn't apply. Maybe paying more than is currently owed on a cumulative basis isn't sufficient to avoid a penalty. Does anyone know if that's the case?
You probably do not owe a penalty, but Form 2210 (the form that calculates the penalty) will not be ready to e-file until 02/24, see availability chart. Since the form is not ready, it is likely that it is not pulling the correct date information yet. Hold up until Form 2210 is ready and see if this issue corrects itself then.
If you really want to file before that (I am not recommending that), there is a box you can check to allow the IRS to figure the penalty and bill you later. If you chose that option, Form 2210 is not included with your return, so it won't prevent you from e-filing. But the best option is to wait until 02/24 or whenever the form is finalized and available so you will know exactly what your penalty status (if any) is.
Why am I getting an underpayment penalty if I'm getting a refund? According to your facts, this would not apply to you as you did pay timely, but it does explain how the timing works.