does this have a dial control that you turn to set the time or amount of drying? Or is it all electronic? If the former, then the timer motor might be stuck or faulty.

Any Oasis model will have electronic controls. It's electronic behind the panel even if there's a rotary dial to set the cycle.

There should be choices for auto-sensor drying or timed drying. I assume the problem you describe is occurring on auto-sensor cycles. Try a timed-dry selection to confirm if the same behavior does or does not occur.