After letting my mind fester for a while on this, i think its actually a voltage spike... not so much a spike as it is more than it was used to before. Hear me out.
This is all just pure speculation mixed with a small amount of electrical experience, i have seen similar issues with relay switches on AC systems for homes and the cause was her voltage from the source needing a buck boost transformer to lower the voltage that was then an issue for the old switches.
I think that the relay or whatever mechanical switches are being worked here are used to my old battery that it had and the older battery i used temporarily. (they were NOT the right size for the rocket). once i change the battery it now has higher amp and voltage output into the same connections that have wear on them, this wear prevents larger contact until its attempted a few times. Basically the same issue that the starter switch has... tons of corrosion that is "ok with the old lower voltage and amps, but cant handle more anymore! Make sense?
The issue is most likely with the components connected to the now correct healthy battery. I have seen stuff similar to this happen but not often enough to jump to it as the primary suspect cause.
I would suspect its NOT a voltage drop issue so much as its a worn out component.
I have what i would call a very high amount of skill mechanically and i would not suspect the battery or the starter as the issue. Not with how much i have invested into putting them into service (starter rebuild ect).