Had the same problem not long after getting my current mk7 golf. So we go to the car to pickup my daughter from school, it started as normal, at the 1st set of lights stop start activated, it started up as normal at the next left turn i brake and slow down quite a bit as is dodgy one. Then it flashes many warnings like stop start and acc not available… but was still running, at no time did it say battery low just virtually every system was not available.
we gets the daughter and car starts, drive to morrisons for few things, Mrs goes in, i had a call i needed to make to vw and car never started again. Rac came and it was the battery, replaced it with a higher rated one as that was the only one he had, not had a problem since the cells was only working at 20% he said.
It did not stop like say if the alternator was not charging the battery, i had that happen many years ago in my first car and no lights, no hazzards, no nothing and no mobile phones then.
Also had a battery cable work lose then the car just died as well.. but I did go over a dip because of road works just before, so checked it and terminal was lose.
So personally i don’t think it could cause the car to stop running once it’s started unless you stall it. but if you have a dsg that’s not going to happen, just ain’t gonna startup again..
my guess is the stop start was gonna activate when i slowed almost to a stop as it does.. and wouldn’t of started again so it deactivated it and everything. a bit like limp mode.
but it should of said battery low, if the key battery gets low it says.. but not the actual battery.. Stupid imo.. Luckly for you, you was at home, not in the car park.