I had a similar experience with WTB Nanos. They went on no problem, and seemed to be holding pressure ok. However after a couple of days they lost all their air and holding them underwater showed small bubbles leaking through the one of the injection moulding "nubbins", even with sealant (Stans no tube). I tried taking them for a ride to properly spread the sealant but this didn't make any difference. Then tried an anchovy but also didn't work. Eventually swapped back to my old tyres and am in the process of patching from the inside before steeling myself for another round of tubeless faff plus potential mid-ride disruption.
TLDR: I have doubts about the quality of the WTB quality control process