Operating system: Ubuntu 18.10
Graphics card: GeForce GTX 1060 6GB
Broken: 2.80beta, 69b2f5268114
Using the attached test.blend, open Blender with no config directory.
Hold ctrl and MMB-drag-up and zoom in -- observe that it stops relatively soon and refuses to zoom further.
If you keep trying to zoom in against the stop (perhaps 5 or 10 screen heights) it "locks" the position of the view.
After that, you can not zoom in or out, and you can not translate the view with shift-MMB-drag. Pivoting the view with MMB-drag still works.
Hitting "home" resets the view and things work again.
test.blend was made using my normal blender config directory; this issue doesn't happen (at least not yet) with the default scene from a fresh install, so apparently there is some kind of config or setting causing it.