that's a weird combination... Python2 goes often with Qt4, and Qt5 with Python3. And yet OCC 7.3.0 is nearly the latest release, with the stable 0.17 ... where did you get your FreeCAD from ? Did you try the latest shiny version ? That's the one I — and many others here around — are using.
Your version is not a stable version either. The fact that some software manager offers it for installation doesn't make things better. Have a look at https://www.freecadweb.org/wiki/Install_on_Unix and install either current 0.17 or as said before 0.18. Noone here knows which bugs your version has, there have been almost 8000 improvements from yours to the current stable 0.17. If you don't want to use something experimental, don't use that version.
Nothing wrong with realthunder's version, but it should strongly pointed out that this is a fork of the official version. It may not work the same as the latest official version. I do not think it is regularly rebased, so it does not have a lot of the recent fixes in the official master version.
there is lots of room for debate around this subject, I'm not sure how strongly you'd want this to be emphasised.
Deep in the FreeCAD source, there is a file (don't remember which, or where) that fills the version info with arbitrary values if the Version.h file is not built successfully. The default revision number used to be 5235, I believe it was changed recently.