[Arran]

This is just an educated guess, since I don't have a model 21, or 70, or 90, to examine, but those cracks very likely line up with a joint in the poplar substrate of the arch molding, due to there not being a layer of underlying veneer under the orientalwood. I don't know if all of the Ed Coombs "Baby Grand" cabinets from 1931 were like this or if it depended on which company made the cabinets, Philco or an outside contractor, I noticed that Terry's cabinet has the top and side veneer's grain running from back to front horizontally, whilst others have it running vertically. it would be interesting to know whether the Canadian built cabinets of that year also suffered from this issue.
Regards
Arran