I'm seeing the "not everything rendered in viewport" issue as well. Here's a couple screenshots to illustrate it, hopefully. This is in b74, just after opening a campaign file.
After opening, at the initial zoom of 100%, the viewport looks like this:
There are normally 2 more of the large red library tokens in that set, off to the right of the 4 visible ones. They are not appearing on screen (which was the cause of some alarm at one point!). However, if I zoom out one click on my mouse-wheel (which takes the zoom level from 100% to 74%), (edited to add
or move the map in any way), the other two appear as shown below. I guess requiring a redraw might correct an erroneous viewport size?
Once I alter the zoom level, this particular visual glitch doesn't happen again until the next time the campaign is opened.