PROBLEM:
The first image is a badge with both images ripped manually from the stack.
The second image shows a common cut on a badge overlayed on the badge of the first image so you can see where in the timing mark it seems to be registering.
The third compares the first badge with the non poly badge (that does properly terminate each time).
There do seem to be some slight difference between the size and placement of the timing mark between the two.
SOLUTION
In Consultation with Epson Development Team, First, we used a 4x3 label to test this material and we were getting the same intermittent skipping. During test run. printing 10 each and it would print 2, skip, 4 skip, 1 skip, and so on. Completely intermittent.
Our support team and Epson walked through all the steps we have done, then they mentioned that the timing mark requires 2 millimeters of space for the timing mark. So what we did to adjust was change our file size from 4” x 3” to 4” x 2.875”. As soon as we did that we have had zero skips since.
I believe a slight adjustment to your size will make the difference you are looking for, please let me know what you think.