2.2.3 FPS drops when preload Armature Info by addArmatureFileInfoAsync

Hi guys.

I want to play an animation when preload data. But the FPS drops dramatically to even less than 10 when I preload Armature Info by addArmatureFileInfoAsync. However, the FPS is fine (above 40) when I just preload images by addImageAsync.I check the codes of both function and find they are nearly the same (both of them load data in another thread). Is it a bug? What should I do to keep FPS more than 30 when preload Armature Info.

Could anyone help me? Thanks in advance.