Cannot delete a site (domain folder is not writable)

Hello!

When I create a site, the domain folder(/var/aegir/platforms/SOMEPLATFORM/sites/SOMEDOMAIN) is writable, but right after I visited 'Configuration' section at this site, the write bit removed from the folder. So when I try to delete the site its done partially: the site removed from the system with warnings about permissions, but domain folder not removed. So re-creating site with same domain is not possible, etc. I need to remove the folder manually after 'chmod u+w' to it. Or I need 'chmod u+r' to domain folder before removing the site via aegir.

Why aegir(or drush?) does not add the writable bit to the folder before removing it? BTW, I changed apache user/group from 'www-data' to 'aegir', chown all www-data to aegir, etc. But may be it is matters anyway.

An example attached.

Help me plz. Thanks.