Yes, i have seen my plants do the same thing... It happened when it first started getting hot and humid. Of course we have had a cool wet spring and then all of a sudden the heat kicked in. They are ok now. I think it was the sudden climate change from cold to hot.I think it took a little time for them to adjust to the sudden heat and humidity; now they are doing fine.
If u had a week of excessive rainfall and then a quick warm up... i suspect that is the culprit. They should get better and adjust as time passes. I wouldn't do anything to exasperate the situation, such as fertilizing or pruning. Just give them time.