Chevrolet 2008 Tahoe Owner's Manual page 46

Q:
What is wrong with this?
A:
The belt is twisted across the body.
1-42
CAUTION:
{
You can be seriously injured by a twisted belt.
In a crash, you would not have the full width
of the belt to spread impact forces. If a belt
is twisted, make it straight so it can work
properly, or ask your dealer/retailer to fix it.