Veins wilting, upper leaves

Looks like mild nutrient burn (browning/purpling on the tip and edges)

The other plants are different strains altogether with different genetical environmental preferences. Coupd just be genetic variance as it's is the primary reason different cannabis strains exhibit unique characteristics, even when cultivated in the same environment. Wouldn't worry yet but keep an eye on it.

more than one thing can cause burnt tips and both toxicity and deficiency possibilities. it's possible you need more of some and less of other things... or the paling is possibly related, too... not enough info. Do some basics now -- ensure your pH is okay. Don't do anything unorthodox in regard to irrigation... hopefully that doesn't require instruction. I'd also try to check the base of tha tleaf -- make sure nothing fuzzy is growing underneath. if it's a slow progression, definitely be patient and let it give some more hints for a better diagnosis. You are entering later flower so some senescence is unavoidable at times or simply difficult to avoid... if it's slow-moving, it's not much of a problem, though. think the 'lightening up' you see is more about grow lights playing with the colors, because in normal lighting some of your diary pictures have the plant is plenty lush (dark) and even shows soem signs of over-feed with some slight curling of the tips. potting up won't stress it, but it probably won't make use of that new volume as well as it would if you let it fill in a larger pot before flip to flower. Even if it does fully colonize the new space, by that time it'll be near harvest.. all the heavy lifting is done by then. This is fixed with a tweak to your fertilization... if you don't have more info than just a leaf symptom, i'd be patient and see how it progresses before overreacting.. also, see if the things you did already have an impact. doing 20 different things justs means you have no idea what actually worked and you don't learn from it -- also, more times than not doing 10 different things will cause more problems than the original issue.

Servus. Seems like a long flowering pheno. And from the looks I'd say she needs food. These sativa can be quite sensitive. Nevertheless, those spots showed up when I fed too less during stretch, when they needed it the most. Good luck Mate..

I don’t think the color looks that bad; it could simply be that the plant is using more nutrients, or that it’s a bit stressed if the transplant was done recently. Since you already lowered the light intensity and increased the root space, it’s normal for the plant to take a few days to settle; more vigorous plants often show temporary sensitivity in the new growth before their color recovers. From the picture you shared, it actually looks quite healthy. Keep it up you’re very close to harvest now, stay high.