Zombies unable to use Frost Walker Boots

I was trying to get zombies some frost walker boots. after a few tries I finally got the frost walker boots on. First I noticed the boots weren't enchanted. I though that it was a visual glitch but then I tested it and the Zombies weren't able to walk on the water. If you want to test it for yourself here is the command.

/summon zombie ~ ~1 ~ {ArmorItems:[{id:"minecraft:leather_boots",Count:1b,tag:{ench:[

{id:9,lvl:2}

]}},{},{},{}]}