Can't make a spicy pickled egg despite my best efforts

My first time making a jalapeno pickled egg, it came out awesome and had a little bit of heat. Every time since I've tried it, absolutely none of the heat is there.

I'm using 1tsp red pepper flakes, 1 jalapeno, 1tsp black peppercorns, and 1tsp Sichuan peppercorns per 1L jar, along with a dozen eggs.

Does the acidity level affect the spiciness? I'm going a lot heavier on vinegar than the standard 50/50 ratio.