ahhhh, ok, so I think I understand. It isn't that your watermark changes fromand in all repeat images he add a 2nd watermark again
"https://rootjazz.com/"
to
"https://rootjazz.com/
https://rootjazz.com/
https://rootjazz.com/
https://rootjazz.com/"
i.e. multiple lines of the same text, the issue is, the program is adding a watermark to an already watermarked image.
This explains why unique doesn't work. It is NOT an unique image, it is a new image, that has been watermarked. Thus it has a different CRC / hash value.
So the question is. Why is the program trying to watermark images that have been watermarked. How are you creating the action. I don't think you are running a normal image upload routine. Select folder >select images specify XYZ to upload. as this would NOT upload previously watermarked image.
Once I can understand exactly, then I think we can find the issue.