Answer: To an extent, this is the normal growth/coloration habit of Gold Standard hosta. My reference reports: "Leaves of 'Gold Standard' emerge a bright green with a dark margin and fade to pale gold with a very light green margin with age".
Also, Gold Standard isn't particularly sun tolerant, and you have yours in an almost full sun spot (6 hrs. and up is considered full sun). Excess sun can cause even more fading. There is a variety called "Royal Standard" that is full sun tolerant.
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