System Information
Operating system: Linux-4.15.0-72-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: GeForce 9800 GT/PCIe/SSE2 NVIDIA Corporation 3.3.0 NVIDIA 340.107

Blender Version
Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-12-04 11:32, hash: rBf1aa4d18d49d
Worked: (optional)

Short description of error
When importing a gltf model and joining several meshes the meshes are broken

The bug is so big that this happened

Here you see another weird color.

I have to do it again, I freeze my pc ..
Well, this is how the model looks when joining it with ctrl + j

This says the terminal

Exact steps for others to reproduce the error
import this gltf file to the scene

select all the objects in the scene by pressing "A"
Press ctrl + J to join the objects and see the Bug.

Other issues aside.
In Blender 2.80 this does not happen, luckily in that version of Blender objects can be joined without problems