It didn’t read to me like it was – I can’t really back this up, though, it’s just how the scene felt to me.

Yeah, same here, honestly.

Do you think them not showing IS the personality change? Like, they became suddenly unwilling to help?

That would be interesting! They were also absent-without-explanation when Zhu Jiu and Zheng Yi invaded the SID, though, so maybe they're leading a secret double life somewhere. :p