I don't know, the mention of Fenrir being a spirit wolf seems to only be in the english version of the item, japanese and french doesn't mention it at all so who knows, the english team seems to add a lot of lore that aren't in the other languages so I usually try not to rely on them, maybe Iceheart is just thinking that this wolf is a moon wolf when she found it in the alabathian mountain while it's just a regular beast, maybe the myth of fenrir came from these in the first place.