When I save the PZ3 the little green "animated" icon next to Ambient Value in the MAT room is ON.  When I reopen the file it is OFF.

But the animation palette still has the shader nodes and the keyframes.  The PZ3 file still has the KEY values and as far as I can tell everything looks like it should work but somehow it boils down I believe to the "animated" button not being ON in the MAT room.  Something is toggling this OFF when I save the file and when that happens the exisinting animation does not work.

After saving the file and reopening it for example the ANIMATED shader node for this mat is still ON using the DIFFUSE value:
 

shaderNodeParm com_display_5_PoserSurface_1

                  {

                  name com_display_5_PoserSurface_1

                  initValue 1

                  hidden 0

                  forceLimits 1

                  min 0

                  max 10

                  trackingScale 0.01

                  keys

                        {

                        static 0

                        k 0 0.2

                        sl 1

                        lin

                        sm

                        k 14 1

                        sl 1

                        lin

                        sm

WHEREAS, on this one the ANIMATED little green icon is OFF - But I can't see anything different other than one above is constant and this one is linear. This one uses the AMBIENT value fields rather than the diffuse value fields:

shaderNodeParm comm_ops_buttons_blue_PoserSurf

                  {

                  name comm_ops_buttons_blue_PoserSurf

                  initValue 0.996078

                  hidden 0

                  forceLimits 1

                  min -10

                  max 10

                  trackingScale 0.005

                  keys

                        {

                        static 0

                        k 0 0.996078

                        sl 1

                        con

                        sm

                        k 14 0.0823529

                        sl 1

                        con

                        sm

                        }

The only thing that is odd is the values I am using here are 1.0 and 0.0 but you can see that it is assigning .996 and .082.
 

Windows 10 - Poser Pro 2012 - 64Bit - 24GB RAM - 4 x 3.40 GHZ processor