This is an example of the usual daily IT magic.
I've installed all versions of STFE i have, from the current down. No version worked with the same symptoms, until 8.0.29 - this version worked.
After i decided i'll continue working with 8.0.29 i got your message and thought, well, i know now, which version is 100% working, lets try your advice, i have nothing to loose.
So i've installed the current 8.0.70 upon 8.0.29 - and look at this: it is working like expected, without going into add-ons management or any other kind of voodoo raindancing. Bug? Feature? Magic?