It seems that some Actors which I generate which only have few bones being animated are not animated at all when using the DX9 renderer and hardware animated vertices.
However I can’t reproduce the problem with EGG models. Like I said only some models with limited animated bones don’t animate in the original game. I generate the Actors and AnimBundles myself so I might be doing something wrong myself, but seems unlikely as everything works fine in OpenGL and the fact that only Actors with only few animated bones give this problem hint that hardware-animated-vertices are causing this issue (as they only work on meshes with few bones, or something like that).
from panda3d.core import *
loadPrcFileData('', 'load-display pandadx9')
loadPrcFileData('', 'hardware-animated-vertices 1')
import direct.directbase.DirectStart
from direct.actor.Actor import Actor
#... can't reproduce the problem...