@badblocks Hello! As I wrote in my email to you, I've been testing this on ewi fingering mode for a few hours and have not been able to replicate this issue. Maybe a bit more practice would solve it?
Otherwise, let me know if the issue persists and we can see some other solutions. Could you tell me what software version you are on and what settings your Sylphyo is set to ? It would be easier if you tried it on the default settings (you can reset the Sylphyo in the menu) so that we can be sure to test in the same conditions.