When you try to ride any Guzzlord as a land mount, it now causes the player to fall into the ground and take suffocation damage. I had noticed this bug after updating to the most recent version, as I typically use Guzzlord as my primary land mount. It appears that this could be due to the fact that the player now sits much lower on Guzzlord when riding it after the update, which causes the player's hitbox to go underground.
All sizes of Guzzlord, except for microscopic (which is unobtainable without the Pokémon editor) appear to cause the player to take damage when attempting to mount it. As a result, the player may end up suffocating in a wall if the Pokémon had been ridden for long enough, which can cause an inconvenience while exploring.