Network Solutions have been front running domains for some time according to multiple sources. It appears that domains that are searched via Network Solutions whois checker are then being registered by the registrar, preventing a registrant from purchasing the domain themselves.

If you go to Network Solutions site and check the status of a domain that’s available, then don’t register it; the chances are you will see the domain registered within a matter of hours directly to NS. This removes the domain from the world availability and can only then be registered through NS at the revised premium price they charge.

The domains are likely being purchased and held in Network Solutions ownership until the potential registrant comes back to purchase the name through NS at the premium price. If the purchase is not made at NS within 5 days, NS uses the same 5 day grace period that domain tasting operations use and they delete the domain. Once a search for a domain is conducted at NS the domain name is registered and only available to be purchased by a registrant at NS.