Yesterday evening I did a flight from YPPH to YSSY in a Boeing 757-200, after surpassing 10,000 ft I accelerated to 345 knots which is 5 knots off from being over speed, I then went into the cockpit view and heard the over speed warning going off even though I had not been over speeding
There’s no glitch. You keep pushing the envelope of overspeeding and that aircraft has no reason to be going that fast. Besides the 757 is an older aircraft in the IF inventory and needs a rework but still doesn’t mean that it should be driven that hard.
The higher the Aircraft goes, the lower the maximun airspeed.
You should at maximun keep your aircraft at 310 knots