On the Qatari t-list the name is: Archaeological site of Al-Zubarah and its cultural landscape
But even by the time of its first nomination for the 2012 WHC the CL aspect had been dropped -I have just checked the AB eval from that year and the site's official title has already changed to simply "Al-Zubarah Archaeological Site". It was then described as "In terms of categories of cultural property set out in Article I of the 1972 World Heritage Convention, this is A serial nomination of 2 sites".
It is at this point that the comment about the site "also being a CL" is normally introduced
The name was carried forward to 2013 but, for some reason I haven't been able to establish yet, it had been converted to "In terms of categories of cultural property set out in Article I of the 1972 World Heritage Convention, this is a site."
(i.e the second site has been dropped or incorporated!)
So, it looks as if the T List name was a "First thought" which got dumped during the preparation of the Nomination rather than something which was rejected by ICOMOS/WHC
By the way - the 2012 Decision asked Qatar to do some work on the under water archaeological aspects of the site but all that the AB eval for 2013 states is that the remains of a series of dhows sunk by the British in "could be underwater". Whether this is enough to justify a connection to underwater archaeology I am not quite sure - I would have thought it would as this comment related specifically to the harbour included within the boundaries -but we could await access to the Nomination file
However I note that the boundaries of the inscribed site of Tyre have been extended "to include the underwater archaeological remains located to the south of the city" so that connection should be assigned to Tyre as well