Magik's Hood team up is LoS based on the centre of the circle.
Void Pentagram Can Fail Due to Center-Based Line-of-Sight Check
The Void Pentagram, Magik and The Hood’s team-up ability, appears to perform its line-of-sight check against the center of the pentagram.
Magik does not need to physically lose line of sight for the ability to fail. She can have completely unobstructed vision of the pentagram and surrounding players, but if something obstructs the line-of-sight check between Magik and the center point of the pentagram, the ability can fail to function.
This can happen with Groot walls, Doctor Strange’s shield, Magneto/Hulk bubbles, terrain, or when parts of the map move, shift, or change elevation.
As a result, the Void Pentagram can randomly stop functioning during otherwise normal gameplay simply because its center-point LoS check becomes obstructed, despite Magik herself still having clear physical line of sight.