This happened on a player-built fence with a roll of barbed wire deployed across the base of the fence posts, and a camo net, with no other structures built onto the fence.
A player jumped onto the wire by accident, and took damage (their character emitted audible 'taking damage' grunts). They immediately moved several meters away from the wire, but continued to take damage (continued emitting grunts, and their gear became visibly more damaged). After 15 seconds or so they became uncon, but continued taking damage and emitting grunts. They died a few seconds later.
This happened with three different players in a short span of time, at the same fence. It appeared as if the player position became desynchronised, with the server seeing the player as remaining in the wire, while we (other players) and the player taking damage saw them as standing nearby at a safe distance from the fence.
The only way to prevent the affected player from dying was to remove the wire from the fence using pliers before the player ran out of health - by doing this I was able to save the third victim of the bug.
One of us recorded some footage of the event and can upload it somewhere, if that's useful.
I listed the severity as 'minor' because it's presumably rarely encountered, but considering that the barbed wire nearly squad-wiped us, it's still quite a serious bug. We were just lucky that this happened on the coast.