Start/Stop Stalls on 1st Restart

I've had my 2016 2.0TDI 150PS Superb DSG since virtually new and it's been pretty faultless so far but recently it's started to stall on the first restart when Stop/Start is enabled. If I leave it a couple of seconds, it'll attempt it again and start OK so I'm not getting the "Restart Engine Manually" message which would be a right pain. It's not every time and there's no specific circumstances when it will do it (cold/steep hills/sharp turns etc). I used to have the auto-brake/hill hold thing on but that seemed to make it worse as though it was trying to move but the brake was still active so I've disabled that and it's slightly better but still there. The car's done just short of 80K and been serviced regularly with all necessary other work such as DSG oil replaced along with the timing belt and water pump when required. It's not a major problem, more of an annoyance especially at traffic lights and roundabouts and I know I can just turn it off but that's not the point, I'd rather it work as designed which as I say, until recently has been just fine. Any ideas as to what might be causing it and more importantly, how do you fix it? I'd rather not have to take it to a dealer (well I wouldn't anyway, it's an annoyance not a major fault and they'd charge an arm and a leg) but would be happy to take it to my trusted local garage with a bit of additional advice/information.

Thanks