Conveniently, there is already a test PDF for this, which is the one for #1008 ... it contains a number of rectangles which are closed both with an explicit line segment and a final h operator. The problem here is that they won't be recognized as rectangles by pdfminer's layout analysis. To replicate:

pdf2txt.py --output_type xml samples/contrib/issue-1008-inline-ascii85.pdf  | grep rect

(there should be 6 of them, but there are currently 0)

This is almost certainly widespread in real-world PDFs (and not just ones created by ArcGIS) since h is defined as:

Close the current subpath by appending a straight line
segment from the current point to the starting point of the
subpath. If the current subpath is already closed, h shall do
nothing.

And thus there isn't anything wrong or non-conforming about including it at the end of an already-closed path. The fix is pretty simple, see dhdaines@28463f2 (PR forthcoming)