Hey Dan. So, you gave the plant time to see if the condition persisted which is good, but unfortunately it sounds like it hasn't resolved. Here's how i look at your situation.
The leaves are most affected at the tip and margin, not more evenly throughout the leaves interveinally.
There's good green color in the bulk of the leaves.
The leaves are clawing somewhat, curling down and even rolling at the tips.
The plant looks otherwise pretty good.
Dark green and claw-down and necrosis at the leaf tips and margins can suggest over-fertilization, particularly nitrogen. With a MG soil base and weekly ferts, this could be an issue. Some chili varieties simply don't like as much fertilization as others, especially as younger plants. Nute build-up in the soil can affect your pH, which can lead to other nute imbalances, so too much nutes can lead to lock-out and symptoms of nutrient deficiency in the leaves. Add more nutes to the soil to combat deficiency and the situation gets worse.
Hydration levels of the growing media can also play a roll further complicating things (in a lockout situation, allowing the soil to dry will concentrate the nutrient salts into less water in the soil making the lock-out worse, despite that the plant was being over-watered and needs the lesser watering). Also, with rocotos in particular, high intensity/duration light also seems (to me anyway) to have an effect on apparent leaf health. My main point is that when things get out of wack - and I don't think your situation is at all terrible - you ultimately may have to simply balance everything and wait it out to some degree.
When I have had a rocoto start to do like yours I have always been successful with the following strategy, but it can take time and, of course, the damage leaves get worse not better:
Move the plant away from any intense light and heat and allow for good air circulation around the peat pot.
Stop all fertilizer for the time-being, probably for at least a couple weeks.
Water with pH adjusted water and, if possible, allow free chlorine to dissipate overnight if you have free chlorine vs chloramine in your water supply - if you have chloramine i wouldn't hassle with neutralizing it though).
Follow general rules on soil moisture versus too wet or dry.
Also - and this is counter to what is good advice in many situations - don't pull any more damaged leaves off the plant until the situation is cured or a leaf gets really bad. My reason for this is because if the plant is nutrient deficient - whether due to pH or salts lock-out or actual deficiency in the soil - it is pulling mobile nutrients from the older leaves to support the new leaves and plant's health. If you remove the leaves that its "cannibalizing" for nutrients while nutrients still remain in them, the plant will need to move up to the next set of leaves to pull nutrients from, thus you would be accelerating the damage to the plant by forcing the plant to attack newer healthy leaves before it would otherwise need to. Even if the plant is starting to get better, the symptoms will progress up the plant and the plant will be increasingly stressed.
Final 2 thoughts. If you do treat for Mg deficiency, treat with a light foliar feeding not in the soil, because treatments to soil could likely contribute to soil-based problems - I don't think Mg is the issue and don't recommend foliar feeding, but I can claim to know this. I would consider a pot-up being sure the new soil is light and well draining. For various reasons, pot-ups cure a lot of problems provided there's enough root base in the plant to support it.
Good luck man!