Tranmsmission failure is rare so I would discount those posts
(and I bet a few have been replaced when the PNP switch was the real
problem).

A common way to temporarily address the PNP switch problem is to
cycle the shift lever through its range about 20 times. This helps
to clean off the contacts in the PNP switch. If the PNP is the problem
this buys you a bit more time. Perhaps this helped in your case.

Also, when our PNP switch failed, allowing the car to warm up and
then turning it off and on would often clear the problem (til the
next cold day). In one case I recall shifting it to a lower gear
induced the flashing light. Shorty after that the PNP switch was
replaced.

You should keep an eye on it since I bet the PNP switch is going.
The good news is it fails slow and won't leave you stranded or
anything like that. Eventually, turning the car off and back on
(or cycling the lever) won't work and then it should be replaced.