Ok, my guess. Not scale but leaf damage. Watch it carefully. See if it moves or spreds. I don't beleave it will. As for what did the damage. I beleave it happened when the leaf was very young and small. May be insect bites or sun burn. I don't know. Waiting for more to reply to this.
BTW it looks like a 'Whitney'?? as far as I can see.

I second Stushs response!!

The little round one look like it to me. I use Safer's Soap on mine, and when they dry up just spray them off with the hose with a spray nozzel, you can also use mouth wash, diluted alcohol, real soap, beer may work I don't know the alcohol content may not be high enough,
Here is another tip if you have ant problems, use chalk the kind that is used in schools, draw a circle around the pot that you want to keep them out of the ants will Inot walk across that line. I just recently learnd of this one. I have been told that flour works well also, I put a layer on my benches in the green house, they are made of wood, no ants or termites so far this year. X my fingers. Neen oil is great for white fly house flys so is that yellow sticky paper I forgot the name. Oops forgot this one, I didn't want ants in my Hoya greenhouse, so used Mr. Clean on the wood branch that they were climbing on to get to them, then go down the rods and chains that I had used for hanging them . Only a few then use a Cotton tip, be sure to check and see if more retured or you missed. Norma