Well it turns out if you have ESET Smart Security (Anti Virus) installed then you need to open it up and navigate to the Web and Email Advanced Setup and check QlikSense in the "Applications excluded from protocol filtering" .
I got caught by this before and clearly I forgot.
If anyone else running ESET Smart Security and experiences the same symptoms this is the fix.
I have an old PC running Windows 8.1 with well-below recommended specs (so slowness is expected) but I've noticed that accessing Qlik Sense Desktop is all-around much faster via a browser (tested extensively in Chrome) than through the application. I haven't investigated security settings but my Windows 8 setup has no third-party security applications installed.