I just tried to block someone on Facebook and...?

[I A]

It won't let me because it says I recently unblocked them and I have to wait 48 hours to re-block them. The problem is that I have not unblocked anyone in the past 2 or 3 weeks, let alone this person in the past 48 hours. It looks like they may have changed their email address, because now I can see their whole public Timeline and posts on other people's walls, whereas last night I couldn't. I have 3 of their addresses blocked (it won't let me block by name or from their page either). Can anyone explain why Facebook seems to be confused? I had a friend try and block the same email address on their account, with the same "You must wait 48 hours response". She had never blocked/ unblocked that person before at all either!
I was looking for the answer to a question about what looks to me like a fluke on Facebook. I didn't realize that this was Yahoo Judgments. The 48 hours part is unimportant, I wanted to know if someone knew how FB could make a mistake with what appears to be an automated system for blocking, or if I did something wrong using email addresses for blocking. If you don't have any ideas, don't post an answer. "Just wait 48 hours" of asking why it matters doesn't address anything but the fact that you just wasted time posting a stupid answer to a question you don't even find valid.

[falsi fiable]

So wait 48 hours and block them. What's the big deal?

Set your privacy settings so only friends can see your information. That way, it doesn't matter whether your enemy is blocked or not. Problem solved!

[Sarah]

Strange!?

[Tali]

What's the big deal? It's just 2 days.