The app is definitely sending &latitude=%LAT and &longitude=%LON when doing a HTTP test. %TIMESTAMP ain't translated either and %ACC seems to be broken data, those two ain't used by PGC right now though.
It seems like it's the test only that's broken though. As long as your URL actually is correct, it will still work, besides the test. The latest version is from May 27th on Play, so it must have been broken for quite a while now.
If I understand this post correctly, the test is not supposed to send real values. In that case, we should remove the testing part from the documentation, or at least be clear about what to expect from the test. We could potentially detect that it's a test and respond with something good.