I would say it it is drying checks,like Ryan said I like to know how old it is before steaming,
old wood will check sometime with steam and green will check with dry heat.I would super
glue the checks and put it some where not to dry and not to humid,like just in the house
and let it stabilize and then seal it up.As long as it don't run off the edge it most likely won't
hurt anything.I have several with checks in them.
Pappy