Why are the effects from this command made potion not working?

Question

In this command, the speed effect, strength, haste, health boost, absorption, jump boost, resistance and haste aren't working. Here is the command:

/give @p potion 1 8193 {CustomPotionEffects:[{Id:1,Amplifier:255,Duration:19999980},{Id:3,Amplifier:255,Duration:19999980},{Id:5,Amplifier:255,Duration:19999980},{Id:6,Amplifier:255,Duration:19999980},{Id:8,Amplifier:255,Duration:19999980},{Id:10,Amplifier:255,Duration:19999980},{Id:11,Amplifier:255,Duration:19999980},{Id:12,Amplifier:255,Duration:19999980},{Id:13,Amplifier:255,Duration:19999980},{Id:14,Amplifier:255,Duration:19999980},{Id:16,Amplifier:255,Duration:19999980},{Id:21,Amplifier:255,Duration:19999980},{Id:22,Amplifier:255,Duration:19999980},{Id:23,Amplifier:255,Duration:19999980}],display:{Name:"Potion of Unlimited Power",Lore:["~CAUTION~ Very dangerous. Use with care.","Keep away from children."]}}

Answer 1

The Amplifier tag is stored to and read from NBT as a byte, with a range of -128 to 127. By setting the value outside this range, it's going to overflow to a different value. In this case, the value becomes -1. Certain effects will do the opposite or have no function if a negative amplifier is used.

You should stay within the -128 to 127 range:

/give @p potion 1 8193 {CustomPotionEffects:[{Id:1,Amplifier:127,Duration:19999980},{Id:3,Amplifier:127,Duration:19999980},{Id:5,Amplifier:127,Duration:19999980},{Id:6,Amplifier:127,Duration:19999980},{Id:8,Amplifier:127,Duration:19999980},{Id:10,Amplifier:127,Duration:19999980},{Id:11,Amplifier:127,Duration:19999980},{Id:12,Amplifier:127,Duration:19999980},{Id:13,Amplifier:127,Duration:19999980},{Id:14,Amplifier:127,Duration:19999980},{Id:16,Amplifier:127,Duration:19999980},{Id:21,Amplifier:127,Duration:19999980},{Id:22,Amplifier:127,Duration:19999980},{Id:23,Amplifier:127,Duration:19999980}],display:{Name:"Potion of Unlimited Power",Lore:["~CAUTION~ Very dangerous. Use with care.","Keep away from children."]}}

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The /effect command is able to use an amplifier higher than 127 because it's directly setting the internal amplifier, which is stored as an integer rather than a byte. But if the player leaves the game, that internal amplifier will be saved to NBT as a byte, overflowing to a proper value.