I am not sure this is technically a bug, but, it is a UI inconvenience which differs from the standard UI methodology.

When you click the "Paid" amount field, it retains the 0.00 in the text field so typing in amount, say $9.99, would result in 0.00999 interpreted and a Paid: amount of $0.01.

Screenshot of behavior below:



I hope this helps

Edit: I'm aware that I can click the X circle to clear it first, it just is an unusual behavior to have the per-existing text remain. It creates an extra step which isn't normal for the platform