@kyleW it can potentially be over watering too if you’re watering with high volume when you water. To me it looks like heat stress and drought issues coupled with water volume issues, not frequency.
When it’s hot and you have no silica in the substrate the plants will wilt faster and drink more water which can cause nutrient issues as well. Silica helps prevent excessive nutrient uptake when it’s hot and the plants need to drink a lot. As far as watering when it’s hot daily watering in black fabric pots is almost a must when it’s over about 85f. At that point it’s about volume. You don’t want any runoff and may need to water multiple times a day. I personally do a maximum of 5% soil volume at a time when I have to water in the summer even if I have to water 2-3 times a day. It helps keep nutrients in the root zone and keeping it moist will help prevent salt build up too. It’s all a balancing act. Simultaneously over and underwatered if that makes sense. Huge volume at once flushes root zone and causes over watering issues like nitrogen deficiency in the lower leaves, but it dries out so fast they wilt and start dieing back like they’re being underwatered. Dial back the volume and slightly increase the frequency and they will recover much faster.