Vapor barrier is an issue.

VB is placed on the interior side for cold climates because this will be the warm area. It will not provide a cool surface for vapor to condense. When you insulate over the VB, you cool it off. It is now insulated from the conditioned interior. Now the cooler VB can act as a condensing surface for warm and moist interior air.

This is not some killer issue, but it's not good practice and could certainly lead to some issues. In practice, it's very hard to say what will and won't lead to failures.

Just keep in mind that many people are incredibly confused about moisture issues and will very confidently say all kinds of bullshit. Even - really especially - professionals that understand some things well and other things poorly. In reality the problem is simple, but the solutions are complex. Empiricism rules the day.