System Information
Operating system: Windows-8.1-6.3.9600-SP0 64 Bits
Graphics card: GeForce GT 740M/PCIe/SSE2 NVIDIA Corporation 4.3.0

Blender Version
Broken: version: 2.82 (sub 7), branch: master, commit date: 2020-03-12 05:06, hash: rB375c7dc4caf4
Worked: (optional)

Short description of error
Creates a hole in the model if different materials are added in edit mode

How to create example file
Use the default cube of blender
in EDIT MODE - CTRL R to cut the cube in middle
CTRL B to create 2 more lines above and below the center line
select all the cube, add a material (say) Blue color
select the faces of the lines add material (say) RED color
the new added color area shows as holes instead of showing the RED color

Exact steps for others to reproduce the error

1. Open file
2. Switch to rendered view
3. Switch to Cycles engine
4. Check with CPU and GPU device