We kicked around a few names but Solver64 won out as it best described it. Unlike all the previous software I have released for these low cost VNAs, version 3 is a 64-bit application. This means a new runtime engine and VISA.
Its possible you are fighting a cable, connector, relay, attenuator ... problem. There's just no way that an attenutor would be off by as much as you show without there being a major problem.
With the release of Dislord's firmware, I have started to work on a demonstration video for the new software. Because of Dislords added features, the Lite will be used during the demonstration. There's a lot to go over. I plan to revisit the transfer relay and T-Check. Just for you, I'll show a step attenuator.
The data that OWO had presented for the V3 showed 100dB. They were planning to push it further.