It looks like the attacker is feeding KataGo dead groups to occupy liberties from within. In some cases, the KataGo target group has two large eyespaces that are each filled with a large dead group. KataGo seems to take for granted that those interior groups are dead, even though they have the liberty advantage of not being immediately capturable.
Maybe the formula is to let KataGo establish a very large group (i.e., large enough to be decisive if killed), but only with large enough eyespaces such as each would include one of your own dead groups within (i.e., don’t let it have any small eyes). One could even play sacrificial invasions, but with the aim of each of your own dead groups having large enough dead eyespace such that it survives long enough to create a liberty issue for the target group. Then, fill liberties from the outside, while hopefully KataGo takes for granted that your interior groups should be dead.
Just quickly playing around, I got this interesting thing to happen, where KataGo simply let me kill a large group:
However, a huge disclaimer here is that I still lost, so it didn’t really matter that KataGo sacrificed that group. I have to pay more attention to the rest of the game, and make sure that the killing of the target group is actually decisive.
However, still interesting to see that I got a KataGo bot (as judged by KataGo analysis) to play such a extremely negative move:
