Steps to reproduce:

1. Open attached project
2. Open scene "GrassShadow"
3. Select "Obstacle" GO and notice that NavMesh Obstacle is disabled
4. Run scene and move Capsule in XZ plane
5. Notice that it doesn't move to the spawn position
6. Exit play mode and enabled NavMesh Obstacle on "Obstacle" GO
7. Run scene and move capsule again
8. Notice that it moves to the spawn position

Reproduced with: 5.4.0p4, 5.5.0b3
Not reproducible: 5.4.0p1