When you take the Troglodyte quest, the questgiver says that they are raiding the [spoilers] for healing elixirs against Withering. However, when you enter their caverns, the message "You are safe from the Withering curse here" appears.
I suggest that the caverns don't protect against the Withering, so it stays in consistency with questgiver's story.
This was bug reported awhile ago, no one got around to it
Or is the cave safe because they are producing those healing elixir's there?