reCaptha doesn't work on reply form

This is the normal comment form:


but this is reply form:



I use Komento 1.5.3286 and Joomla 1.5

My problem is:

When someone leave the comment reCaptcha for NEW comment appears normally. When I reply comment the reCaptcha doesn't appear. Why? What is the problem?


BUT: When I use Google Chrome in PRIVATE mode reCaptcha appears on reply form.


COULD YOU HELP ME?....

If you want I can leave site details.

Thanks!!!