It’s difficult to find the cause of the issue unless Asobo actually make some investigations to it. It seems random and some are always happening on the same approaches and STARs. So it’s difficult to say what caused it.
All we know is that, be ready when it happens, and make the necessary adjustments. Think of it as a “instrument failure” conditions and it’s the challenge for us pilots to make a decision on how to fly the plane through these instrumental failures.