The plant with dried and cupped leaves looks like an issue with heat stress. With heat stress or underwatering, it is common to see wilting, leaf rolling and cupping, as well as leaf edge scorch. Leaves may turn pale green or yellow and then fall off. All of these symptoms are visible in the photo. You may also see shrivelled blossoms and fruit and/or premature flower and fruit drop. I don't know why one plant is showing symptoms and the other is not, it could be due to differences in sun exposure or soil type. Container grown plants tend to dry out quickly, I recommend watering daily when temperatures are above 90F. There are some diseases and viruses that cause red spots on leaves, but it looks like this may be dieback of a few of the older leaves. Check the leaves with spots to see if the spots are on both the upper and lower parts of the leaf or only the upper part. Do you see any abnormal coloring or growth on the underside of the leaf? Do you see any spotting on the stems? Have the spots grown or progressed? A nutrient deficiency can also cause discoloration. Do you know the pH of the soil? Have you fertilized the plants (if so with what type of fertilizer, and how often)? The answers would provide a few clues.