Something visually wrong with the engine tester, each engine type should come with it’s own exhaust manifold, i see that you have the v16 one set up but the reality is somewhat different, the exhaust manifold ports that aren’t being used will draw in air because of the depression caused by the exhaust gases, this will determine a false reading of the lambda sensor (excess oxygen sensor), which will enrich the fuel mixture and the engine give false readings to the dynamometre. It’s just a visual mistake.
Well said! Yes strange bug there, should be fixed tomorrow 