Changing the F125 - can it be easier?

[HPsauce]

So an interesting test today. Started all looking normal but after a few hundred yards the D highlight went out.
From then on the car generally started behaving as if in Sport mode - late upshifts, quick downshifts, higher revs etc. Though I did before long flip into "real" S mode which worked as it should with highlights on the S and gear numbers if I used the Tiptronic buttons on the steering wheel.

I pottered around in 30/40mph limits locally and noticed that when I engaged Cruise Control it immediately felt as if it was back in D, not S. That was 100% the case over a few minutes of back streets including some reversing. After a reverse the D symbol illuminated only very briefly and behaviour reverted to S style.

BUT oddly after a little while more, without me doing anything, it changed to normal D behaviour (Only, no highlights in the DIS) and stayed that way for a few miles until I got home.
Handbrake on, foot on brake pedal, didn't touch the shifter! Grabbed VCDS laptop from the glove box and plugged it in - F125 definitely showing. Z3/1111.

So basically at present it's driveable as I can use the Tip buttons to upshift if it's inappropriately stuck in S mode. And if it drops into D without me doing anything that's fine.

Anyone got any thoughts on that?