Does anyone else have this issue ??

I noticed the other day that if I push the lock button during a call it hangs up the phone on iOS 4.0.1 ... anyone else having this issue ?

Nope. Mine locks the screen even when in on a call.

Mine has done that since the 3G.

Same thing here. If I am on a call and I hit the lock button it will hang up the call.

May reset all settings and if that doesn't help restore and if that doesn't solve it ... Apple here I come lol

nope.. lock button while on a call will lock the screen... atleast on mine...

Ok here's what i found out.. when connected via bluetooth or earbuds... it locks screen... now while on a normal call without being connected that way, it acts as a end call button.... tried on 3gs, and 4 at apple with 4.0 or 4.0.1

Are you locking the phone when you hold it up to your ear? Or while on speakerphone?

it was one of those things that happened while trying to remove bumper for one set of ear buds i have since the shield is bigger than the bumper allows and i was connected to a call... normally i have buds or bluetooth connected.. 3g and 3gs i never noticed since there was no bumper hence I never used the sleep button during a call lol