Pushback bug when colliding with multiple objects

[BuBuMan]

Steps to reproduce:
1- Set up two sphere objects with a relatively large scale. (8 for example)
2- Keep a small space between them so the character cannot walk through
3- Try to move the character through the small space
4- Notice how the controller starts to jitter and may lose control over it. The controller might also go through the ground.

Here is a picture to elaborate more on the setup:

The bigger issue is the fact that the controller may go through the ground and might escape the level.

[blue00]

Here an image with the same problem using box colliders: