i got issues with the infusion also, it does not work when you have legendary skins (tried only with heavy armor from pve). when you enter combat or just draw your weapons the infusion covers only the skin of the character. looks like this: https://imgur.com/a/efcfwiN
not sure if its intentional, if yes then its a shame imo, i was looking forward to having the whole armor turned to stone ^^ (my armor is black and red, also tried it with another set thats white and blue, did not cover any part of it)
edit: just saw the comment from another person pointing this issue with lege armor out ^^;