When and where did the Captcha come up? So far I have never seen it pop up during forum search while being logged in.

Now if you haven't loged in to the PGD site for some time it is posible that the captcha ocured as a prevention measure to posibly detect if some Bot might have managed to break into an old users accout. If my memory serves me corectly AthenaOfDelphi did mention once that she set that any user that hasn't been active for longer period must verify that he is indeed a human (that is done by using captcha). If that is the case the captcha system shouldn't show up again unless you "go away" for quite some time.

But if the captcha system is still poping up to when you are logged in you please do provide more information as to which steps are usually required for it to pop up so we can check if that is as intended or not.

Also do take note that after 15 minutes of inactivity on the site (15 minutes since last page was lodaded in your browser) the system automatically logs you out unless you have used permament login (checking the "remember me" checkbox). So it is posible that website already logged you out before you were executing your search which could result in captcha in poping up as a prevention measeure for web bots not messing up with the PGD site by spamming the search.