If KataGo were trained using (the rather non-standard) Trump-Taylor counting rules, it would not pass (one should never pass until all areas are filled). If KataGo system claims to have an option to use Trump-Taylor counting, it has probably been added as an adhoc extension to the system and by mistake. At best the paper has found a programming bug in Katago. Writing a paper about a programming bug would certainly sound less glamorous than claiming "we beat professional level Go AI".

The below comments include a detailed discussion of different technical rule sets.

A short description is as follows: the adversarial policy uses rules as follows: "after two passes everything that has not been explicitly killed is considered to be alive".

With such a rule it is clear that no one should pass until all territories have been filled so that there are only individual eyes left (single spaces that are completely surrounded).