Missing fonts and out of place interations

I have courses that are having an uptick in issues with the font and interactions that are out of place.   For the fonts, it was dropping the Is and Fs and spacing the lettings unevenly.  For the interactions, they were click interactions, but the button/object were either not in the right place on the slide or missing altogether.  Our company is using IE and Edge, the problems are not consistent and is hard to replicate.  Sometimes switching browsers fixes it, sometimes it makes it worse.  A few rogue users have Chrome, and it is inconsistent on that too.  Not one browser we try is working better than the other.  After reading the discussion HTML and Missing Fonts Issue and a few other discussions, I gather it might the output format.  I recently moved from publishing flash w/ HTML5 fall back to HTML5 w/flash fall back  which is recommended.   Knowing that flash is going a way soon,  I do not want to convert ALL of the courses back to only have to convert them again when flash goes away.   Are there any fixes or recommendations?  Would publishing in HTML5 only help or make the issues worse?