Oh dear, a similar thing happened to me, and I'm sorry to say that the situation didn't improve for years.
Similar thing, my Yorkshires were indisputably the best for miles around. Golden and puffy, and this all came to me quite effortlessly. Even my (now ex) mother in law had to admit they were the best. How could she not? The evidence was in the clean plates, full bellies and satisfied smiles around the table.
Then, one grim sunday, despite having changed nothing in my ingredients, preparation, recipe or cooking they started coming out flat. Horrors! I persisted for a while but nothing made any difference.
This situation carried on for years and I eventually decided to stop attempting Yorkshires. Then a few months ago I decided to have another crack at it, and JOY! They came out like golden puffy clouds of lovliness! I've had repeated success since then.
I'm convinced I had a curse on me, and I think I know who cursed me. What I don't understand is, why the curse has been lifted, I'm just happy it has.