What does it mean if my cold air is coming out of the air intake vent?

This is what I'm reading online but if this is a new development I would call a professional company: "This can be a normal occurrence if the return passages such as joist spaces, outside wall spaces, etc are used. If these passages run thru unheated areas or areas that are drafty because they are on an outside wall with no insulation, then yes, with the fan shut off this cold air will transfer to the heated area of the home via the return grille. Check out any passage that has an outside wall rim joist that is not insulated or sealed ,thus allowing cold air from the outside to come in."

I would contact a local AC repair service to take a look

Did this just happen? Is any cold air coming out of the supply vents?! Have you had any work done in the home recently?! Are any of the supply vents closed or blocked?! When is the last time you replaced the filter?! Dirty filter would be a restriction and the air needs to go somewhere same for closed or blocked vents so the air backs up. A defective thermostat in the "on" position can switch to a higher blower speed that the ductwork can't handle.

I used to live in a very old house that was poorly insulated. The wall and floor grates always had cooler air coming from the ducts when the furnace wasn't running. In my current, updated home, it's going to be heating season and it's time to have things checked out before it gets cold. Good luck!

Leaks in your ductwork means that cold, unconditioned air from inside your attic gets sucked into your ductwork. That cold air mixes with the warm air from your furnace, causing the air coming from your vents to feel considerably cooler than it should.

Is your system on when this happens? Sometimes cold air drops out of our vents when they're open even when the system is off, since cold air drops. But not sure if that's what you're asking.

The hose came off or you have. Hole

You might need to have an HVAC company come out and take a look.

It means the air intake air valve has failed or is failing, call a professional HVAC .

There is a gap somewhere where cold air is getting outside instead of inside. Check to make sure everything is sealed. You may need to contact a professional AC repairman to find what is going on.

Does this happen when the heat is on or the ac or all the time?

I have an issue with my return vent in the bedroom. instead of recycling room air, it blows out hot air which makes the room temp more than 80 degrees. What also baffling is that it blows hot air even when the heat is turned on in a different Zone. That is; my bed room is in zone 2, but when I turn on zone 1 while zone 2 is off, the vent still blows out hot air. I subscribe to one of those home appliance repair insurance and when the guy check it out, he told me to clean my vents without providing any help. Any idea what is going on?

Time to get the unit serviced.