Weird change of ocillator during playing

I have a strange problem and I don’t know if it’s due to a lack of knowledge about sub-options or an option that has been activated without my knowledge, or if it’s actually a problem.

When I’m playing on patches, at a certain point, oscillator 1 changes randomly and completely transforms the sound. This happens without me even touching any buttons on the desktop.

Do you know what’s going on?

Thanks !