If Liam thinks highly enough of you, he’ll have given you the quest “Liam Kosta: Day Out on Aya” when you talked to him on the Tempest after rescuing the Moshae. It’s a simple enough quest to get out of the way now that you have access to all of Aya. Talk to him in the Tavetaan and he’ll ask you to scan some merchant’s wares. Strange way to hang out, eh?
Head to the Marketplace and try to scan the wares Xaan Ingil is selling (not to filthy aliens, though) and you’ll quickly get shut down by some guards. Return to Liam at the Tavetaan and he’ll explain he was trying to use subterfuge to gain intel that diplomacy failed to obtain. Respond as you will to end this quest and gain some XP.