As quoting of UID  is mandatory for filling of IT returns, for Individuals, since 1s t July2017. I am the opinion HUF does not considered as an individual,( being a ENTITY-sepearte from a individual). This  COMPULSORY DIRECTIVE is NOT APPLICABLE(presumed) that Karta of HUF should link  his individual PAN, to HUF IT returns, as it may create HAVVOC/ CHAOS at CPC as his UID will get reflected/ linked with both IT returns as INDIVIDUAL and with HUF too, thus finally  may get either or both IT returns decided as DEFECTIVE, by CPC ( compuetrised system-No human interfrence)....please through expert LIGHT on the same.