YAY for being able to eat eggs! Maybe you avoided them long enough that your body adjusted. That's what happened to me with eggs - I avoided them, except for "incidentals," is how I called them - like, if there was an egg in some bread or cake someone else made, I didn't sweat it. But I couldn't eat them by themselves or in an omelet or anything. I was that way for about seven years, and then POOF I could eat them again. It was marvelous.
Maybe you should separate your eggs by breed of chicken and see if that makes the difference, why you were fine a few times and then had a minor issue another time. Like with cow's milk, Holsteins make A1 and A2 protein milk, but some breeds like Brown cows and Jersey cows only make A2 protein milk - and the A2 protein is fine for some people who can't tolerate A1 protein milk at all. They think they're lactose intolerant, but they're fine if it's A2 milk (a friend of mine just recently tested this theory after avoiding milk for years, and discovered she could drink it if it's A2!). There was also a clip I saw from a BBC news show where they were talking about a study where people were testing to see if it affected people with autism. So for the sake of the show, they arranged to get just A2 milk for this family with a little girl who was autistic - severely so, to where she regularly had meltdowns from being overwhelmed and she couldn't focus on schoolwork or anything. Granted this was just one kid for the sake of the news show, but after she had been drinking only the A2 milk for a while, the mom said she hadn't had a meltdown ONE TIME (when normally she had them a lot), and she was doing schoolwork, too. I haven't heard if the official study is done - I saw that clip a few years back and maybe it's a long term study, I don't know - but that's wildly interesting.
Anyway, so maybe some chicken breeds have something different about their eggs, and you're okay with some but not others?
I remember your amazing egg story, and have kept it in the back of my mind, you told me to keep trying! I have been picking the really tiny eggs to eat, white, pink and green shells. I will conduct experiment!! Only tiny eggs, and one colour at a time, let's see if we can haz correlation!
Let us haz!