reCaptcha does not submit correctly with Random Captcha (from Captcha Pack)

reCaptcha does not submit correctly with Random Captcha (from Captcha Pack)
reCaptcha works OK when selected directly from Captcha.

Log message:

Type CAPTCHA
Date ...
User Anonymous
Location http://.../user/register
Referrer http://.../user/register
Message user_register post blocked by CAPTCHA module: challenge "Random CAPTCHA type" (by module "random_captcha_type"), user answered "", but the solution was "1".
Severity notice

Tried combinations:
- CAPTCHA 6.x-2.x-dev (2009-Feb-06)
- CAPTCHA Pack 6.x-1.0-beta2 OR CAPTCHA Pack 6.x-1.x-dev (2008-Apr-07)
- reCAPTCHA 6.x-1.1 OR reCAPTCHA 6.x-1.x-dev (2009-Feb-02)

Cross-filing to all 3 projects.