I have my player(rigidbody, capsule collider) running into a cube(rigidbody, box collider). They both have the default physics material, and the player has freeze rotation constraints enabled on all axes. After the collision the player produces no OnCollision callbacks. Then if I disable the player’s freeze position constraints collision callbacks continue. Changing the collision detection mode of the player made no difference. There’s no weird code inside of the OnCollision functions, only a debug log. I’m not doing anything weird with the player’s rigidbdoy either, just setting the velocity, the same bug also happens with add force. So the rigidbody just sits there, with no gravity pulling it down even though use gravity is enabled, and no collisions.
The player’s rigidbody was falling asleep.