Budgie regurgitating?

As my budgie (female) started moulting, she sometimes began to put her head to one side and nod her head, as if she were regurgitating, and to make a move at the end that resembles beak grinding, she never spit anything out. This movement was always made near her food and didn’t stop after the moulting period ended. Another change was that she became quieter, but I assume that is because the season changed and the weather is gloomy.
Due to my inexperience in budgie sickness, I am worried, especially because I don’t have near me a veterinarian specialised in buddies.