Here's what I wrote 3 years ago about this:
I have a large tree of what is now known as Redland White Sapote. I tasted it at the F&S Park back in the mid-90's and thought it was one of the best White Sapotes I had ever had (overtaken, subsequently btw by my trying Younghan's Gold). At that time, Chris Rollins was calling the tree "Not-SES 2" for what became obvious reasons, when the tree fruited and it looked nothing like SES 2 which the label said it was. It was later named Redland. I grafted bud wood and got a successful take and planted it out. What I most liked about Redland was the lack of any bitter aftertaste that I had encountered in some White Sapotes. And as you said, it does have a very nice florally flavor. My tree grew large ad began producing.....but sporadically. And, to my chagrin, my fruits all had a bitter aftertaste. Now the tree fruits very infrequently if at all. I have hacked the tree back, fertilized it, minor elemented it, sprayed it and nothing. It has now been relegated to dragon fruit trellis status. I posted in the Yahoo Group a question about why this might have been. My post was largely ignored. My thoughts at this time are that the rootstock may be the issue and may affect the fruit flavor. Or, it is a soil issue, or it is both a rootstock and a soil issue. I am 100% sure that I did not mix up the budwood....as I took no other bud wood of white sapote from my visit to the F&S Park that particular visit with Al Will's class. Anyone else have any ideas?