First of all, that's not densifolia. It's Hoya cumingiana. And the leaves are normal. The pinched look usually comes from some type of mechanical damage during the leaf's early development. Check for pests, first, especially mealybugs, scale, spider mites (need a magnifying glass to see these), and aphids.

If no bugs are noticed, then the mechanical damage was done by something benign, like the stem brushing against something, while the leaf buds were very newly developed.

Thank you! I just checked the differences of the flowers, and you are absolutely right, it is a Cummingiana!

I see no bugs, so I guess it is mechanical damage... I was worried it was something nasty like a virus. Thanks again!

You are very welcome :)

Another good way to tell the difference is the leaves. Densifolia has leaves that are egg-shaped, and cumingiana's are more acute: