Thank you Ciero. I too suspect this is a hold out from their byzantine past.
For those interested this is what I’ve found thus far.
The funeral meal usually hosted by the family was common in both Judaism and pagan religion. however the pagans alone were very big on laying out food and drink, money, gifts, crowns of flowers, etc. for the dead at graveside as offerings or appeasement or whatever.
Augustine condemns the graveside practice of offering things to the dead. He makes the point that the dead have no need of such things and it is the living poor that should receive our gifts. "He linked care for the dead with care for the living, bringing together, in a sense, two “invisible: ends of the community”
Chrysostom too condemns the practice of lighting candles at the tomb, offering food and clothes on the 3rd, 9th, and 14th days after death. He too says that the dead don’t need this stuff but the poor certainly do. Later Gregory Nazianzen disapproves of the libations and first-fruit offerings still going on by the graves.
Also the apostolic constitutions warned Christians not to overindulge at after funeral meals (parties) but it did not completely forbid them. Somehow the practice of having koliva at the grave continued, but not as an offering to the dead but to the living. What was once a party full of drinking and dancing changed into a memorial meal shared on the various days (3rd, 40th, etc) after the death of a Christian, each day having a very Christian significance.
My sources were Alexious, The Ritual Lament in the Greek Tradition and Paxton, Christianizing Death.
I still see a lot of “offerings” left at shrines I wonder what the Fathers would say to this?
I have also see it served at Italian funeral meals (Roman Catholic) so who knows?
But it was all for fun if one actually threw it. Not required. This is the only mention of kolyva/kutia for Ukrainians, on Christmas Eve.