After changing oil + filter I followed very closely instructions at page 95 of Owner's Manual to reset FSS. First The ignition key set in Position 2. Then within 4 seconds pressed twice Zero Button. Then within 10 seconds moved key in Position 0. Press + hold Zero button for over 10 seconds.

Instead of getting a sound and 10,000 miles display I observed 27,009 miles displayed on the second line, while on the first line (trip mileage line) displays -0.0-

Could the software running this resetting have bugs?
Is there any other explanation?

Try to closed All doors in order to reset FSS system.

All doors where closed when did procedure.

You have to turn the ignition key back to position two while holding down the "zero button" ...continue to hold the button down for the stated time interval. This should reset the FSS display.

Boy, they could have made this more simple for the consumer. I have gone through this time and time again here.

Ignition on. push button until you see the wrench.
Quickly turn off ignition THEN push the button and hold it while turning on the ignition. Hold this position for over 10 seconds. You will hear the beep, then let go.

Good luck

PS, there are no bugs in the software. It works.