This magnifying glass effect is a pervasive and dangerous (to thirsty plants) garden myth. Don’t let sunshine stop you from watering a plant that’s suffering from lack of water. https://s3.wp.wsu.edu/uploads/sites/403/2015/03/leaf-scorch....

Thanks for busting that myth. Foliar isn't about hydration state, it has chemicals and surfactants and it's recommended to do it in morning/night. according to this AL extension office, it can causes a phytotoxicity (leaf burn) at high leaf temps (probably because higher uptake rate of the chemicals) https://www.aces.edu/blog/topics/lawn-garden/foliar-feeding-...