Romans cremated their dead. I don’t understand the burial thing here.
Romans didn't always cremate their dead, that's what's going on here.
They did so some inhumations. I’m thinking in particular of some books I’ve read about the excavations of the necropolis under St Peters in which there were ashes in a. Umber of graves, but also plenty of bodies buried. There was also the Roman custom of installing tubes down into the graves through which libations could be poured. Maybe this is a variation of that, or the deceased was a romanized local, as burial of grave goods was widely practiced in a number of cultures