This is a really cool project!
It looks like sometimes attempts to select and copy a string duplicate the string in the selection for each layer present. For example:

Similarly, copying the "80px" in a different example produced the following clipboard contents:
80px
80px
80px
80px
80px
80px
80px
80px
80px
80px
I believe this is mostly just an artifact of how layering is accomplished, but that the results were inconsistent is what I find most curious - further attempts to replicate this seem to result in only one copy in the clipboard ( though an extra line feed seems to be tagging along as well )