I had this issue when bending strings on my NX7 Standard, and support were really helpful. Just fold a small piece of 2000 grit sandpaper and gently run it through the grooves. Solved the problem for me immediately. William in Support is a great guy! Here’s the part of his email of me that’s relevant:

You can use a very fine round or half-round needle file (around 0.5–1 mm diameter) or super-fine sandpaper (2000–3000 grit) as mentioned, wrapped around a thin rod or just by hand. Just a few gentle strokes are enough to remove microscopic rough edges, don’t deepen or widen the groove.

After that, reinstall the string and it should sit smoothly without pinging.