Intermittent but loud whistle from VESC

I am getting an intermittent high pitch whistle from my VESC. Pretty much anytime I pump or turn, or at higher throttle. straight and low throttle there is no issue. It does not seem to be causing any damage or performance issues, Just quite loud and anoying. Trampa 75/300. This is a second board with all the same guts and the first never did this. Any ideas?

Are you sure its from the VESC, and not the prop?

Check the water inside the VESC.