SOIL what damages leaves like this

[Cunjo420]

Found one caterpilliar looking bug 1cm into the soil.
I often clean plant from aphids.
I know leaves discolour becase of Magnesium but I dont understand this white spots, white damaged leaves. is it bugs eating or what. plant is slowly dying from the bottom I dont want to lose this orange bud haha.
from start until now I used 0 nutrients. Only good quality soil

 

[Ace1973]

looks like a ph fluctuation

 

[3Berries]

Said they weren't using nutes, maybe drying out too much causing the pH swings?

 

[Helie]

Agree with the Ace1973, ph fluctuation is the most possible reason

 

[alltatup]

Those light brown spots don't look like pH fluctuation at all: it looks like something nibbling or something splattered onto leaves and burned a lil bit.

pH problems never cause "spots" like that that I've ever seen before. A systemic issue like that will not appear sporadically, but consistently on leaves.

https://www.growweedeasy.com/cannabis-plant-problems/caterpillars