If you’re not aware of it, then you might need to double and triple check your settings. Assists has to be set to Hard/True to Life. (Taxi Ribbon is the exception) And AI Copilot has to be off at all times.
Either you have double bindings in your control somewhere, or phantom inputs coming from your keyboard. Or the assists is “fighting” you by changing the flaps to the way it wants instead of what you want.