Hello friend
So almost every topping and usually fim too is going to cause a slight delay, it's unavoidable. I don't think these leaves are caused by the top at all. Right now you're running at 100 degrees(my yard is too), and is it really only getting 5 hours of light..maybe direct hours? If you have leaves falling off then we need to get this plant some nutrients...nitrogen based, so a "grow" nutrient.
Also with the heat being so high, I've been watering my plants almost everyday, or every other day, to help battle the heat.
A good plant tonic is kelp/seaweed extract, and a silica supplement helps with the whole grow also.