Is there a Gremlin in my Kawai es8??!!

[betreich]

I'll try and keep this short but hoping someone may be able to throw some light on this...I am beyond frustrated.
Bought a new es8 Feb 2017 having begun piano lessons in my retirement.  In June middle C had developed intermittent problem, no sound when played and occasionally a very loud sound. Kawai authorised repair and piano tech Paul replaced a strip of contacts.
November saw Paul back again...low C similar problem. Contacts replaced for the entire keyboard.
Yesterday Paul back...low C problem again. A whole new contact assembly was installed.
So....played fine last night (short session), fine 30 min session this morning. This Arvo...played fine to 45 mins...then very loud response to playing middle D (as in made me jump) this repeated intermittently for the next 15 mins or so, when I gave it a rest. Back for another go after about 2 hours....fine for an hour, then that D started intermittent shouting at me.
I plan to call Paul after the weekend....any tech people here have any ideas or have any other es8 owners had similar repetitive issues? And I do look after my keyboard 😁
Thankyou

[betreich]

So, in case anyone was wondering about the outcome....this misbehaving key seems to have resolved itself, no more problems after about 3 days, and thankfully I did not need to call the piano tech. Will just have to remain as one of those mysteries of life.