You took your car to the dealer with the Jb1 installed? Takes about 10 minutes to unhook, if you take a coffee break. The value of these piggyback units is that they are easily removed prior to visiting the VW dealer, retaining your warranty, but I guess your ‘15 passed its warranty long ago as mine did.My car (a 2015) had a broken valve spring some two and a half years ago.
The local dealer I had it towed to (not my usual dealer) had it for a week or two and couldn't even figure out what was wrong with it.
I had it towed out of there to a VW/Porsche/Audi specialty shop that found the problem.
I had a jb1 on it at the time, but have no idea of that had anything to do with it.
In any event, I had them remove the jb1 when they performed the work.