Hi akshatpatel, I haven't found a consistently reproducible scenario but I can mess around and try to find one.
It definitely still happens - earlier today I right-clicked to move a tab to "New Window" and it just vanished. no new window opened. I tried with 2 more tabs and the same thing happened. (I could have recorded this but don't want to risk showing any sensitive information.) For a little more context, each of the tabs that vanished today was some Atlassian web app.
So I'll open some new windows and see if I can reproduce this with regular sites.
EDIT: Oh, this was before I upgraded though. Maybe it's resolved in the new version.
EDIT 2: Slightly more information, possibly only making this harder to diagnose: While minimizing my Orion window just now, I found a second window behind it, which was on one of the pages I previously "sent" - but didn't have that tab in the tab list. Sorry, I don't really know how a screenshot could be helpful here, especially as I'd have to redact the URL and tab content.