If they were wet, then probably they have been conserved this well because of the high acidity of the water they lay in. (In the netherlands we have several 'bog bodies' who are well conserved as well because of the airtight situation of the bodies being burried beneath the bog and high acid water, effectively sealing it.) It makes sense that it begins to rot fast after those coffins were opened, because that would mean no airtight situation anymore and oxigine would get in, this overall change of circumstances would make it possible to continue the process of decay.
About Bog People Cheers
