avoid replacement of "@" char to "%40" in SSO login page

@ char to

Hi!

How can I avoid replacement of "@ char to %40" on SSO login page in username field after (for example) wrong password entered.

Enter "user@domain.com" as username -> enter wrong password -> click enter -> SSO message authentication failed and username changed to "user%40domain.com"

I've use OAS SSO 10.1.4.3.

Thanks!