I just got the Green Herb in my own save (Month 5), at this spot:tested it and it worked for the blue herbs in a shiny point that I hadn't triggered the bug on but couldn't get green herbs, so either green isn't working or the point was consumed when the bug was triggered, probably the later but I don't have a save old enough to confirm. I attached my current save right before blue herb collection.
edit: added an old save during correct time for green herb collection to show bug (save 9)
I tried looting the same spot on both of your saves, no luck.
Seems your point-consumption theory is probably right, sorry to say.
Thanks for the report, won't have to happen to anyone else now that it's fixed.