It could be a case of you didn’t fix the problem and it didn’t go any further and the plant grew big enough to take the nutes from the soil and seemed healthy.
The 2nd pic the soil is too hot for the seedling, transplant to lighter soil it’s getting burnt up! The 1st pic seems to show some rusting on the leaf which could mean an early calcium def, don’t think it’s the light bro.
Tuck them leaves, if some fan leaves yellow then chop them when they are close to dying, imo the more leaves the better buds even if some bud sites aren’t getting light, at some point you will lose a few anyways! :) don’t chop healthy leaves, been there done it and it was a mistake.
You’d have to be a dumass to mess lst up bro, simpliest thing ever, there are plenty of videos and threads/pages etc and tbh toppings even easier, saying that I only topped when I first grew, then next time around lst’d And never went back lol.
Looks like nute burn to me guys, how much are you feeding and what? If it was n def or lack of light the lower leaves would turn all yellow first, they are not.
Tbh I rekon it’s had too many nutes, no nutes just water, what soil is it in? It’s a baby remember, that soil probably has enough in it for the plant already!
Calcium and magnesium are two different things, so you can’t have a calmag def, however yup looks like you need to add calcium, how long have the leaves been like this? Did you add calmag before the leaves looked like this or after? Tbh the light green also indicates you may have a magnesium...
Sometimes it shows in veg (depends how long you veg and how much room you have) or around 1-2 weeks after you switch to 12/12, I suggest vegging no longer than 4 weeks if you don’t have a lot of height in your grow space.
I agree calmag tends to be nitro heavy and usually chemical! So if your in soil that’s not the best! It’s the calmag that’s making the leaves dark as hell, definatly cut back dude.
You should be all good then! When the plant gets bigger you’ll need to transplant ready for flower into a bigger pot, at that point you’ll need heavier soil like bio bizz all mix (example), good luck :)
Should do great in better soil! Just make sure it doesn’t have a lot of slow release nutes as it will kill your seedling off in no time, has to be soft soil dude!