If it's 60 days, that could make it awkward for this challenge, as it has a 60-day window.
How so? If that's true, you can replay a quiz the moment it falls off the list. Actually, this would kind of confirm my theory of it being 60 days - the challenge can only track back 60 days, so once it falls off, you can replay.
If you are referring to replays for low scores, it looks like the "Biggest Fan" challenge is missing the needed link. You need a special link to erase a low-scoring play so you can retry it, but the challenge does not have it.
Guess that needs to be fixed if it's what you're referring to. (I could think of a workaround, but that would be convoluted, require help from a second player and not work for quizzes you scored exactly 5 on. (Also, it would kind of abuse a site feature. However if you absolutely need it to finish a set, PM me and I'll tell you how. Not your fault the challenge is missing the replay links.)