missing letter!

5/6 of these arrived on Cranberry Island for the Island Mailart Exhibition.  Apparentl 'L' is outstanding.  Why does that happen and how will it change things?

Island Castaway?

When I was in Kenya Sabra sent me a card of Christo's wrapping of Manhattan - one of my islands.  A paint sample colour took me to Christo.  The word castaway  made me hear the theme tune from Gilligan's island.  Did you know they only ran for three seasons? It felt like my whole childhood. As a teen Patrick Denver came to Cranberry Island, my real island, for the summer.  Patrick was John Denver's son.  John Denver was Gilligan.  We had Gilligan junior on our island.