VDC OFF light flash on a Legacy 2.5 GX AT my 2000

It has done 2 times.
After one hour running on highway at 60 MPH start the mountain road but
my legacy don't run, pushing the throttle pedal, instead of kick down
the "VDC OFF" light switch on.
Everything return normal after turning off and on the engine.

I have purchased my car which has 94000 km, now has 118000, I make
service at 100000 and 112500 as Subaru prescription, by the local
official dealer/service, which by the way, make all service of my car
from it's born, but I don' trust him.

Can anyone help me?

--

"Steu" from Italy