When we are running XPSImport on a Policy Server with cache updates disabled, the import does not complete. The import seems to freeze at the same point:
[19843/1][Wed Apr 05 2017 13:16:41][XPSImport.cpp:1116][DoImport][INFO][sm-xpsxps-05820] Import complete.
[19843/1][Wed Apr 05 2017 13:41:46][XPS.cpp:369][XPSResync][INFO][sm-xpsxps-07535] Policy server notified.
[19843/1][Wed Apr 05 2017 13:41:46][XPSImport.cpp:538][XPSImport][INFO][sm-xpsxps-05820] Import complete.
Even if the XPSImport doesn't seem to complete, all the objects in the Policy Store are correctly updated. After the objects are imported into the Policy Store, the XPSImport tool sends a command to the Policy Server to tell it to resync the cache. Policy Server checks and loads the changes from the Policy Store. This is what it is causing the problems as you don't see the XPSImport completing and ending due to having disabled the cache update previously, which makes the Policy Server not answering back. The tool keeps waiting before ending the process for that answer.
This issue is fixed in R12.52 SP1 CR08, so to solve the issue upgrade to this version.