Hi Anand,
Although Standard Bookmarks are user-specific, they can definitely be shared via the URL for the bookmark, as that is what bookmark URLs are intended for. This applies to URLs for all bookmark types.
As you've pointed out, the issue may be related to the version of the Design Studio NetWeaver Add-on being used. For example, there were issues in DS 1.5 as described in SAP Note 2168161.
The only other possible cause I can think of is security.
Regards,
Mustafa.