[Bug] Monsters' second phase is not working (arm muscle icon)

[pfyy]

Did you look for other closed issues that have the same problem?

Yes, and I think it is not fixed and mistakenly closed. #1170

Describe the bug

The monster ID is 29060203. I think the explanation in #1170 is wrong. There is no such thing as another monster ID for the second phase of a certain monster.

Which branch did you use?

1.4.3-dev-855d318, almost the latest version of GC

Screenshots

Additional context

[pfyy]

BTW, the monster that goes into the second phase simply freezes. Boss 29060203 just freezes there and does not attack. It could be an unhandled packet or something? Further studies are needed to resolve this.

[pfyy]

closed for it is consistent with the behavior of GIO server (gm command monster)