When a potion is thrown directly upwards or downwards, it goes slightly more forward than it should. I believe this is only the case for splash potions and no other projectiles, but I'm not too sure. When thrown upwards or downwards, the potion should fall generally close to the crosshair but goes too far forward instead.
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We're tracking this issue in MCPE-138995, so this ticket is being resolved and linked as a duplicate.
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