It is not possible to add a link to an archived version which is not a snapshot of the exact same URL as the original weblink. This is however not a bug, but a feature necessary e.g. to ensure that people do not add "replacement sources" which might work in one context but not the other.

If a live version of the same website exists under a different domain, the dead link should be replaced. If the same information can be found in an archive snapshot of a different URL, the link can be replaced as well (perhaps using a bot if the number of links is large). However, all these cases require human oversight and need to take a link's context into account. That's beyond the scope of IABot.