I've hesitated to post itt because usually I can back up whatever I post and I'm not up to diggin through this again right now so please take it for what it's worth and investigate further if your heart desires.
First off I can't agree with what I'm about to say because what I found was very complex and I couldn't wrap my head around it. I took a very deep dive into this a few years ago but it would have taken some severe effort to continue and self educate and in the end it didn't seem worth the effort.
So in an almost literal read between the lines type of situation from my own personal lameass meta analysis it seems to be something to do with carbs rather than protein. I told ya it didn't make sense lol.
BTW in previous discussion on this and previous boards I'm sure
@Sorbate will remember that many replies were something like "bubbles are normal, relax bros". But I've been pissin with this same (fucking massive if you must know) peener for nearly 6 decades and I know what a normal amount of bubbling is. What I'm talking about is the times where for a few days or weeks their is a solid inch and a half of bubbles covering the entire bowl. No dietary, training, lifestyle or supplement changes that I could note when it happened either.
That's all I got...