But in this case the testing is given different amounts of time.
The thing you think works gets less testing time than the thing you aren't so sure works.
Thus the thing you think works is more likely to pass, just because you are subjecting it to less tests.
Your bias (whether you think the thing works) is having an effect on the outcome.
Good testing, as with good judging should involve 0 preconceptions.
Yes it could be that the judge has a good eye for how long a topic will take, but leaving less time for the facts to come out, necessarily means the facts are less likely to come out.
Then if we test it and it fails acceptance testing, I might learn there is a problem that takes some time to fix.
I did not arrive at a biased decision; I had priors that I used to make an estimation, which turned out to misleading.
The judge is exactly this case. They guess the time it will take to rule; it doesn’t have to mean their eventual ruling is biased.