The only insight I can provide you is... You are not alone. Android Central's comment system is flat out BROKEN! I lost count of how many times I've commented and still get the friggin' CAPTCHA. Last week, I even saw a post that was spam and yet an on-topic comment I posted was "flagged for spam" and brought up the CAPTCHA.
By the way, I do not have this problem when posting in CrackBerry or WPCentral, only Android Central is that irritating when posting comments. Well, I don't post in TiPB, PreCentral or NokiaExperts so I don't know if those are OK or are as broken as Android Central.