Accusnap takes 5+ seconds past a certain zoom point

Using a 4k external display with no DPI scaling. Does it on both my internal laptop display and the external when it happens.

It will eventually register and snap, but it takes a significant amount of time. Tentative snap works fine. 

I have had the drawing I am working on open for 5ish minutes now, and it finally started working how it should at any zoom level, but it's inconsistent. Changing the accusnap sliders make no difference