How to reproduce:
1. Open attached project
2. Enter playmode and open the profiler
3. Inspect Draw Calls in profilers 'Rendering' tab
4. Change editor game view to some custom portrait resolution (Tested: 1440x2560)
5. Inspect the Draw Calls again

Expected behaviour: All objects marked as 'Batching static' batched into one draw call resulting in 4 calls total
Actual behaviour: When in portrait view the draw calls increases into hundreds (depending on the resolution)

Reproduced on: 5.5.6f1, 5.6.5f1, 2017.1.2p4, 2017.2.1p1, 2017.3.0f3, 2018.1.0b1