2011 Volkswagen Tiguan shut off when stopped

I bought a used 2011 Volkswagen Tiguan on
Monday and on Tuesday when I was driving it, the
car shut off while I was at a red light and I had to
turn the key to turn the engine back on. I took it to
the shop on Thursday and they told me that there
was something wrong with the oil separator and the
air pressure sensor was dirty. They’re going to
replace the parts to try to fix it, but I have until
tomorrow to return the car. Is this a red flag should I
return the car or keep it? It runs perfectly other that
this problem and I rly love it. Is this fixable or is this
car a lemon?