Subdomain redirect to default site after login when it shouldn't

Hi,

I'm not sure its a domain access issue and i apologize if it is not the right place to ask that kind of question.

I configure subdomain using domain access.
Got in addition the following submodules:Domain Blocks, Domain Theme, Domain Toggle.
Modules that can effect login: LoginToboggan, Pathauto.

When user tries to login to the subdomain it get redirected to default domain.
To make it clear - after the redirection the user is not logged in - only redirected to front page of the default site.

Here is the redirection rules in htaccess file:
RewriteCond %{HTTP_HOST} ^sub.example.com$ [NC]
RewriteRule ^(.*)$ http://www.sub.example.com/$1 [R=301,L]
RewriteCond %{HTTP_HOST} ^example.com$ [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [R=301,L]

Please help.