Frost shield increase your mouvement speed +8% doesn’t work

Wizzard Spell :

Frost shield bonus 1/4 increase your mouvement speed +8% doesn’t work.

1/4 : 0%
2/4 : 6%
3/4 : 14%
4/4 : 22%

Instead of

1/4 : 8%
2/4 : 16%
3/4 : 24%
4/4 : 32%

Device Type: MOBILE
Device Model: Ipad 11 m2
Device Operating System: IOS
Diablo Immortal App