Maya Api Node not working with keyframes

Hi,
I have a file node with an int attribute that changes the image.
When I manually change the attribute works. But when I add keyframes
doesn’t work.
Any idea why?
Cheers,
-Alex

this problem is most likely because the plug you test for in the beginning of your compute is not the plug that is triggered in playback,
so if you use a compound plug make sure that also the children of this plug are checked