Viewport doesn't update until clicking off of art, or hitting Alt key (seemingly specific)

For some reason, my AI has been acting up after an indescriminate about of time working, my viewport stops responding with realtime updates to changes (any, creating shapes, moving any object, type, etc. doesn't matter what it is), the object in question shows the bounding box/controls/handles etc., doesn't show the changes registering, until I click off of the artwork, or press the Alt key - that the view / artboard registers the changes.  

I've checked my preferences, settings, updated my gfx drivers, switched between GPU/CPU, checked between realtime drawing and editing on/off, changed the auto-save / background features on off (not working with overly large files)... not sure what is causing it. but as it's a fairly minor inconvenience - but only restarting the program will rectify, it gets to be very annoying. 

I do utlizie HotDoor CadTools as my only 3rd party, and don't have an overabundance of fonts/brushes.