Steps to Reproduce:
1 /give @p tipped_arrow[custom_name='

{"italic":false,"text":"Arrow of Decay"}

',potion_contents={custom_color:3484199,custom_effects:[

{id:"minecraft:wither",amplifier:1,duration:200}

]}] 64
2 Go in the inventory and hover over the item
Expected Result:
The duration of the effect should be 220 ticks, or 11 seconds.
Observed Result:
The duration of the arrow is 10% of the original value. The value is treated as 1/10th of a tick, and therefore must be 2200 to have an effect of 11 seconds.