Actually, the two points were closely related. As explained in the thread oo_.SmoothedVariables, I was looking at output from old estimation runs that had not been deleted from the oo_ output, and I was confused about the co-existence of oo_.SmoothedVariables.VARIABLE_NAME and oo_.SmoothedVariables.MOMENT_NAME.VARIABLE_NAME.
Thanks, Johannes, for the offer to send up the code. As so often, the urge to produce a cleaned set of files with reproducible results was enough to give the decisive clue to the cause of the problem.