When the mouse is hovered over a tile benefit icon (such as the "haven" icon shown in this screen shot) the tooltip window is too small. I did get it to flicker to an appropriate size, but then it flipped back to the too small size after a couple of seconds. This happened on the first colonization of a planet, and when viewing the home planet (earth). The save file shows it well.

This screen shot is at https://www.dropbox.com/s/e0va4gg3trt0328/Screenshot Tooltip Text window too small.png?dl=0

This behavior is also happening when hovering the mouse over items in the Technology stage 1 window and the Tech Tree ("Research Technologies") window. It appears so identical to the behavior I saw in the planet window that I suppose the cause could be identical. The screen shots are at
https://www.dropbox.com/s/95cgje9ukemow4a/Screenshot Tooltip Text window flickers shot 1.png?dl=0
and
https://www.dropbox.com/s/u6g5hr4mkrop3zw/Screenshot Tooltip Text window flickers shot 2.png?dl=0

This exact same behavior occurs on the Ideology window items "Mindfulness", "Affinity", "Radiant", "Pragmatism", "Greed", and "Terror". In short, most of the Ideology items that contain at least three lines of text plus some "unlocks" items.

I am unable to identify (as yet) any specific characteristics in the Planet View or the primary research window that seems to be tied to this behavior.