I have a similar but unrelated problem by the sounds of it...

With no warning at the beginning of the week my audio-jack started to only intermittently recognise that headphones were inserted...though the headphone-daemon will pause play when I remove the headphones even if the device has not overtly registered their presence (ie. not channeling audio to them or producing the headset icon in the status bar).

It is currently in the shop 'awaiting parts', which I assume to mean a new audio-jack.

Apologies if this is irrelevant...