The quick and easy solution, maybe the only working solution posted here (sorry Tony), is to go into your list, find that species, and manually delete and re-add it. It will then take the correct date.
“Reload from observations” will only affect species listings that are not on the list, it won’t “correct” ones already on there, as far as I’ve worked out. So while that will work if you delete the species from the list, then use “reload from observations”, it is a needless extra step.