Here is a pic which shows the variegation.

Hoya memoria is a totally different plant from davidcummingii.

Davidcummingii flowers (logees):

Hoya memoria (Dough Chamberlain):

Hoya memoria was called gracilis until it was published as memoria. Gracilis is no longer a valid name. Davidcummingii was also called gracilis, in error, which is why people why buy gracilis/memoria think they may be getting a variegated (wrong there, too) form of davidcummingii.

About being wrong about variegations:

This is a variegated hoya (Gardino's-kerrii variegated):

This is an albomarginated hoya (mine-carnosa Krimson Queen):

And here are splash leaves, like (and including) memoria (mine):

aff. waymaniae:

curtisii:

memoria (mine from another thread on here):