I've earned 6 bronze badges in Area-51, but it shows 3 everytime, except when I go to a proposal page or discussion zone. May I know the reason behind that? Is it a bug?
It's the same as on 2.0 meta sites and has the same meta badge set. Just as on site metas the badges (with the exception of convention and quorum) are earned separately.
Your three badges on Area 51 (Pioneer, advocate and autobiographer) are both different and separate from the seven badges you have earned on the discussion zone, just as they would be on any other meta site. Pioneer and advocate are not available on discussion.
I'd be very surprised if this wasn't by-design =)
First one is your main area51 user profile that refer to commitment proposal, example questions etc...
And the second one is the discussion user profile that refer to global Q&A you made.