Why do I still have a Yellow Attention Logo on Garage Tab?

Each car has various paint jobs that are unlocked as you play the game. They will not show as "new" with the exclamation point until the appropriate car is selected. Select each car (equipping it), then move to the paint job tab to see the new paint jobs that are unlocked.

Select every car and go trough all the tabs. It's something unlocked for another car.

It's a bug, I have all the DLCs that come with the game, and I have everything checked out, just like you. But the exclamation point is still there. I still don't know why they haven't fixed it. Maybe no one has reported it, who knows? But I know for sure that it is a bug.

Edit: Check every car and every decal on it, since all cars unlock new decals and it doesn't put an exclamation point on it.