Do you have other layers? Are any other eggs funny tasting?
we’ve had the occasional off tasting egg, and usually we don’t know why-we can just speculate. , and it wasn’t a Continuing Problem. However, last year I was playing around with a few things believed to increase egg yolk color, and would feed them one item for several days, along with normal feed, take a break for a few days, try another one. So, none of them made the eggs taste funny except the turmeric I had sprinkled on/into wetfeed. It wasn’t a whole lot either, but enough to make the eggs taste really off - and very slightly turmeric (but maybe that part was imagined since I knew they had been given turmeric). those eggs did not taste chemical, however.
maybe take a walk around to really assess what the can get into. Is there a spot behind a shed or garage that might have some contaminated soil? Any standing water that is attracting bugs or is itself being used to drink from? Can they eat through a fence items from a neighbor yard?
but, if no other girls are laying off flavored eggs, maybe it is just her! You can always use her eggs to cook up for the girls and feed back to them. Maybe after she molts, things will improve.