Lovely blooms Lin
I also got Hoya pubicalyx this year, still young I guess, and like yours some leaves getting that reddish hue..so I have been moving it around to get a good shade.
I hate aphids
I remember when it attacked the new growth of my schefflera, the only thing that got them out was a mixture of water, alcohol, dishwashing liquid and tabasco sauce applied early in the morning before the sun hits the plants. Aphids begone!