Windows phone phantom touch event

I have implemented a custom touch control - it is basically a box collider that loops through all Input.touches and determines which touches are in the colliders bounds.

However - I have noticed an Issue with Input.touches when used on my windows phone device. At random times while playing, sometimes 30 seconds, sometimes 5 minutes - the Input.Touches list has a phantom touch event inside it - showing a size of 1 even with all fingers off the screen.

This subsequently causes all OnMouseDown() functions to fail since they rely on the primary touch.

Has anyone else encountered a stuck touch? Can I detect and clear out stuck touches myself? Restarting the application causes the bug to go away - but I dont want my users to have to deal with this.