This doesn’t seem like anything to many people, does it? This is exactly the reason why you need a professional and experienced Inspector.
The white vent is an improper installation of a bathroom fan, in between two gas appliance gas vents( furnace and water heater). Even though this is not an air intake, it is badly deteriorated and given the right weather conditions, gases will flow back into the house through that vent .
That is kind of dangerous and must be corrected.