I subscribe to the MonMusu stance and proclaim that Yoshika is usually not stiff as stretches is part of her routine, possibly with Meiling every morning- Huh? 🤨 Has it ever been explicitly stated that her joints are stiff? Ah! Once it seems, in her omake, but followed by Seiga recently recommending stretches.

Note that the first panel is "勅令 随身保命" which would mean something like "Imperial Decree: Follow and Protect". This is a popular phrase to draw on Yoshika's seal, as it's used in a famous Jiang Shi movie. That is to say, unrelated to the comic itself and in practice part of Yoshika's design.