Several of the PDF 1.7 FTS files are rendered with incorrect fills when converted to XPS using the xps write device. For example: bin/gs -sDEVICE=xpswrite -o test.xps ./fts_02_0216.pdf I've checked and the xps viewer in Windows 7 displays the Ghostscript generated xps file the same as GhostXPS, so the fault is in the xpswrite device.
Fixed in commit aba8c4b3961892998fafc276defc47b90e35d0e7