I got a red mandevilla a few months ago and it all seems to have a handful of these puckered distorted leaves with dark brown spots, especially along the tips and edges. I can't be sure if they begin with the specks or they appear later on. There's also leaves that turn yellow and drop when you touch them from time to time but it's always looked otherwise healthy and it's still putting out beautiful flowers to this day. I can't find a pest on it even under close inspection. Is this normal? Could it be diseased?