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).
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”.