Do pandas despawn naturally?

On a server I play on I went on a journey to get a panda. I breed 2 pandas and left one baby and one adult panda on a boat. I buried this boat in a 2x2x2 area underground. When I returned to get my pandas they had both disappeared and all that was left was a zombie in a boat holding bamboo. How did this happen? Did

• someone steal my pandas
• my pandas despawn
• my pandas get killed by a mob
• something else

Pandas can't despawn, and I see no reason that a player would take the effort to lure a zombie into a boat and put bamboo in its hand. It's likely that Minecraft just glitched and replaced the pandas. That would explain why the zombie would have a piece of bamboo in its hand: The bamboo stayed, but the panda was replaced.

The panda could've possibly died by glitching into the walls while on the boat. It's pretty common for boats to suffocate entities when in cramped rooms.

Another thing that makes me believe that the panda suffocated to death is the fact that a piece of bamboo was left behind; when pandas die they can sometimes drop bamboo, when a zombie spawns in there is a chance that it's a zombie that can pick up items left on the floor, and if the zombie ends up pathfinding with the boat nearby it could board the boat.

Basically what I think happened here is that; the panda on the boat suffocated into the walls of its cramped hole, the dead panda dropped bamboo and left the boat vacant, a zombie which could pick up items spawned inside this 2x2x2 hole and picked up the bamboo, and the zombie ended up walking towards and boarded the boat.