7 months with only a ziploc? i think yes, these feeders have lost their scent.
the behavior you describe seems to agree with that as well: the snake clearly smells prey, but is likely "confused" when the wiggly thing in front of him doesn't smell stronger, so he doesn't strike. Yellow exhibited the same behavior before i bought new feeders (along with regular refusals tho he seemed hungry).
i say bite the bullet and get new feeders. i guarantee you'll come back to say "I'VE NEVER SEEN HIM STRIKE SO QUICKLY"![]()