I can't reproduce this. I tried the following test script and the alpha properly animates with the texture:
Code:
import viz
import vizact
viz.go()
#Add textured quad
tex = viz.add('dot.tif',wrap=viz.REPEAT)
quad = viz.addTexQuad(pos=(0,1.8,2),texture=tex)
#Add environment
viz.add('gallery.ive')
#Update texture matrix of quad every frame
def UpdateTextureMatrix():
quad.texmat( viz.Matrix.translate(0,viz.getFrameTime(),0) )
vizact.ontimer(0,UpdateTextureMatrix)
Does this script work for you?