Just to further clarify this, it extends to ALL CoF drops (CoF tagged or not) that cannot be traded, as stated in the FAQ section:
Do all items dropped when in Circle of Fortune have a Rank Requirement?
No. Only items which dropped as a result of benefits from Circle of Fortune will have a Rank Requirement on them. However, All items dropped while in Circle of Fortune cannot be traded. This is indicated on the items.This is to prevent a burden of optimal play scenario where players would feel pressured to either switch Factions occasionally, or in the more likely case have a second character level as MG just to be able to sell those high value items you might find as CoF that aren’t tagged CoF.
We still want some items to stay as non-CoF tagged, so that switching from CoF to MG would be less painful, and for cases where MG and CoF players play together, as in that case all items found by the MG player would be usable to the CoF, while some items found by the CoF would still be usable by the MG player.