Honestly speaking from experience, after mine failed. VW are full of sh!t!!
I think this is a problem and a big one TSB released in the states and TSP ( I think the UK equivalent) has been released in the UK. They don't do this for 1%
Also the same garage that fixed mine said the same thing to me "Never heard of this happening before"
Turns out another forum member had his in there 4 weeks before with the SAME fault, new engine and service was trying to tell me he had forgotten about this GTI being there! hmmm
However as soon as I PUSHED my beloved GTI onto the forecourt 6 mechanics all came out to help push and said in unison "Tensioner failed mate" all nodding. You don't get this from 1 %
And finally when the garage logged the fault code the factory in Germany offered a new engine 100% parts with not even a minute to consider it I reckon if this was a small issue they would and a full diagnosis to see WHY this has happened OR if loads have failed they know why and thus a process is in place if the engine throws that code then new engine we have heard enough...
Just my opinions of course but as I mentioned in my fix thread if you hear a rattle on start up for only a few seconds I predict 6 weeks. Trust me you know your GTI as I do and I knew when this noise appeared on start up that was never there before and after 6 weeks she never started again....
Good luck by the with yours hope it's not this and something simple & cheap but if its gone £650 is the winning repair bill............ set by myself of course