Registering CAPTCHA rejected, but key sent anyway

Problem: when trying to register, the captcha is reported to not have been correctly filled in – but the key is sent anyway:


The form cannot be sent
Please correct the information below and try again.

Re-type three letters in the box:
Please fill in the three letters

This happens as much as you try again (I today tried 6 times – and still reporting that “form cannot be sent…”) – but after a while I also got 6 emails with the key (always the same key).

You can fill the (new) three letters many times – they are almost always rejected. I had it also that about the 10th time it was declared to have been gone and accepted and I was told that form was sent; but anyway I got as many eMails as I filled in again.

Btw: JavaScript turned on; MSIE; XP