When a player is controlling an entity, (whether saddled or a boat), the player gets highly reduced upwards momentum.
To reproduce:
Mount a horse with a saddle
Get moved upwards by a geyser
To observe expected behavior:Remove saddle
Get moved up by geyser (and observe higher velocity)
The same behavior can be observed with boats.
This is likely the same behavior that wind charges have on player-controlled entities.
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