Captcha not resolving

I'm having trouble getting past the Captcha for WHMCS from within my site. I saw a question at https://premium.wpmudev.org/forums/topic/captcha-having-issue-when-new-user-registers-if-they-get-the-captcha-wrong#post-258012

but I think this was a SetPassword issue, which I don't have installed. I do, however, have AntiSplog installed and it seems that may have something to do with it. Any thoughts?