From my long experience as a CC owner, "pending" doesn't mean a thing.
AFAIS, these are former invitations either by them or by the CC owner which have not been accepted. In such lists of random CCs, I have found people who had joined other CCs, as well as people who had become members of said CC (via another invitation?).
Thus, it's only garbage - either delete the entries (if you are the current CC owner) or leave them for good - it makes no difference!