Agree, however, in my case specifically I still think it can be linked to loosing to much NaCl during exercise. I do like to push myself harder than most, but after almost all my sessions your can literally wipe the salt of me. My gloves, headband, helmet liners, shirt, bib etc always show plenty salt lines as it dry down.
For me, it must be a combination of pushing too hard and sweating like a pig .... 🤪
PS: During my Comrades years my training was always "perfect" according to the experts and yet I still got cramps towards the end.
