Low chance to deflect Ghast's Fireball (MCPE)

In the nether, Players can deflect ghast's fireball with small chance. I've deflected ghast's fireball for 6 times but nope. It won't deflect and I died because of this ghast. knocked me into lava oceans. So I lost my best items in the nether after respawn with Respawn anchor. No matter what, my Netherite sword with enchantments of Sharpness V,  Mending I, Knockback II, Fire aspect 1 and Unbreaking II was lost, not only my sword but all my Netherite ingot stored in my pocket and also all my items too.