Off white spots on leaves.

My plant is two months old autofem growing outdoor in high 24c 9c low temp and 8-10 hrs of direct sunlight.

Its been stunt for nearly three weeks in the firat month due to wrong info by a member here but now its growing good but a little bit slow.

I feed it two days ago with half strength hydroponics nutrients A+B+C and suddenly its showing off white spots on leaves here and there and i can't notice any insects or molds (or maybe i can't see them without a microscope, but my plants are on the roof and they are getting plenty of wind and low, med humidity)
and there are tip burns too, i think i shouldn't have used the hydroponic C solution with A+B and maybe i should lower the strength more next time!

So what is causing those spots?

their you go ...you just can't trust this internet thing these days
perhaps you can give an example of this False Advice and from what member..?
just to ensure it don't happen again ...

I can only presume this is a re vegged plant considering the 'round' leaves

this grow is your first, for perhaps Shit and Giggles as you typically failed to name the strain

18yo on here please

Yes it's my first grow and i am learning more so next time there will be no space for mistakes and i am waiting for white widow autofem seeds to arrive next month and the weather will be better.

I am growing northern light autoflower fem on peatmoss, perlite and lime and when the seedling was 10 days old he told me not to give it any nutrients yet so they were stunt for nearly 18 days and then i started to give them nutrients and they started to grow again.

So what's causing those spots?

Anyone?