With quilted jackets in the vicinity it's not possible to see them or what they contain (if they contain anything) on the inventory screen. They have to be taken to hands.

In the VMC military base, upstairs in the prison, I swapped my damaged field jacket with a worn one. My damaged jacket contained a cooking pot (with a MG5K mag inside of it) a compass, 9x19mm rounds, and a few other small items. After swapping the jackets my damaged jacket had disappeared. When I went downstairs in the room below to see if it had fallen through, it had glitched through the floor on the room above and was stuck on the ceiling of the room below. Obviously too high to be able to reach or show up on the inventory screen.
A similar thing happened when I swapped a jacket containing items in a wood cabin with a jacket containing no items, and again upstairs in the prison on Green Hill both times the jackets went through the floor. In the wood cabin I was able to retrieve the items from the jacket, but not on Green Hill as I couldn't seem to find it upstairs or in the room below. I can't be certain on Green Hill, but in the wood cabin I had a cooking pot inside of the jacket.
If I remove all of the items first, or put the items into the new jacket before swapping them, the problem doesn't occur.

The quilted jacket problem has persisted across multiple versions for me for some reason. But the jacket/floor problem has only happened in stable 1.07 and 1.08, and doesn't seem to happen every time.