Yes, this was reported by users using this type of headset. For some users, it got to a point that they cannot use the phone because it gets stuck on the headset mode.
I am assuming that you just using the headset for regular phone calls? I started using blue tooth headsets just to avoid this.
One user even asked how to open the phone to fix it:
how do i take the 650 apart? (to fix the jack)
Do this at your own risk, only if you are a regular tinkerer and have done this successfully for other devices.