I'm not sure what is going on with this tree. It gets strong sun in the afternoon, but nothing excessive. At first I thought this might be a fungal issue of some sort, but now I'm not sure. Thought I would tap into the collected wisdom here on the Forum for some ideas on what this might be... Thanks!
ohh boy, looks like you have maplefreckleitus.... i know bad joke -10. is it covering all the leaves? how long has it been in that spot?
K4, it looks like a combination of mild chlorosis with premature color and leaf burn to me. Sometimes I get some blotchy mild chlorosis just because of soil heaviness, I know that's not normally a problem for you though. Otherwise maybe bacterial? -E