Let me rephrase, with the engine off, the value shows as "LOW". When the engine is running, the value is showing as "FAULT".
From the workshop manual:
"The instrument cluster is hardwired to the oil pressure switch. When there is low (under 41 kPa [6 psi]) or no oil pressure, the oil pressure switch remains closed, removing the ground to the instrument cluster. When sufficient oil pressure exists, the oil pressure switch opens, providing a ground signal to the instrument cluster. The instrument cluster monitors the oil pressure ground signal and commands the low oil pressure warning indicator on or off according to engine oil pressure."
Also, an oil pressure switch failure would supposedly set a C1284 code.
Your IC light appears to be working correctly. The oil pressure switch seems to be working correctly. And Forscan says "Low" when the oil pressure is Low.
Forscan also says something different than "Low" when the oil pressure is not Low. So it is picking up the changed state. Unfortunately, it seems the programmers chose to use the word "Fault" rather than "OK" to describe the changed state.
Unfortunately, I don't have a Taurus anymore to check if Forscan says the same on mine.