Usually I found the 2nd boss would shoot 2 electricity blast while having to push the rocks into him but recently he only shoots one at the start with the rocks and doesn't start shooting 2 until i get to the stage with the power ups? is this completely RNG or triggered by something?

Spike has 2 modes: Easy and Hard

Easy Mode: P1: 1 shot at a time, 2 rocks to end phase P2: 2 shots at a time, 2 rocks to end phase P3: 3 shots at a time, 2 rocks to end phase Other: Chickens spawn

Hard Mode: P1: 2 shots at a time, 3 rocks to end phase P2: 3 shots at a time, 3 rocks to end phase P3: 4 shots at a time, 3 rocks to end phase

Easy mode is most easily triggered during an Any% run, where the egg count is lower. There are many causes for "easy mode" but I don't have full documentation on it. Nitrofski probably knows the most.