That is quite the puzzle.
I didn’t pick up on anything in particular, but that doesn’t mean someone else won’t.
I’d have thought that if you had a batch of questionable eggs, that you’d have seen that clear up pretty quickly after not using them or using a different batch. I have had that happen before. But anymore, I’m quite picky about where I get eggs and rarely even get any at a grocery store. (I’m always out poking around the countryside looking for someone raising chickens on pasture.)
I tend to get butter and cream of the organic variety. I’ve never had any trouble with butter but sometimes cream that’s of questionable quality has given me some mild troubles leaning towards what you describe. But that’s usually pretty short lived for me.
Not to get overly graphic, but when you say “loose”, are you meaning “a little soft but still has a shape” or is it more like “almost totally liquid”? (I hate asking questions like that but… I’m sorry.)