GetItemInfo() returning lots of nil values

[LudiusMaximus]

I got a bug report for my addon suggesting that my call of

local _, _, _, _, itemMinLevel, _, itemSubType, _, _, _, _, itemTypeId = GetItemInfo(itemLink)

with

itemLink = "|cff0070dd|Hitem:157953::::::::120:255::25:2:1487:4785:::|h[Bilewing Helmet]|h|r"

is returning a lot of nil values (in particular for itemMinLevel):

_ = nil
_ = nil
_ = nil
_ = nil
itemMinLevel = nil
_ = nil
itemSubType = nil
_ = nil
_ = nil
_ = nil
_ = nil
itemTypeId = nil
(*temporary) = 120
(*temporary) = "player"
(*temporary) = 120

Or am I misreading the error message?
Unfortunately, I do not have this item "Bilewing Helmet", so I cannot try to reproduce this behaviour.

Could anybody have a look at this for me or give me another idea of how to approach this?

Here is again the bug report with the full error message:
https://github.com/LudiusMaximus/Bag...Level/issues/1

Thanks!