Strange jittering/stuttery behaviour on agent, navmesh seems to be the cause

Godot Version

4.2.2.stable.mono

Question

Sorry for the vague description I’m going to give you, but I’m stumped as to what is happening. I’ll explain the events and hope somebody has some clue to at least point me in some direction.
I’m making a game where an NPC chases the player. I had designed a test map and baked a navmesh for it, and the NPC moved across it without any problems. At some point, I designed a new map and baked a navmesh for it, but somehow the NPC’s movement was all wrong: it was stuttering, sometimes leaning for an instant, which you will see in the video. I started looking for differences between the new navmesh and the old map’s navmesh, but found nothing. At this point I had two maps: my old one which worked fine, and the new one with the glitches in question. At some point I pressed “bake navmesh” on my old map, and to my surprise it generated a different navmesh even though I never modified the NavigationRegion3D node or the map, and I didn’t change to another Godot version. I playtested this navmesh, and encountered the same glitch.
Video of the NPC, a green capsule, chasing the player.

What could be causing this?