Answer found after much digging on Crystal's site. (it was reference #81 returned by the query "Subreports CanGrow"). When using subreports within a detail band, right-click on the details band to split it into Details A and Details B. Do this as many times as are needed to put each subreport into its own detail sub-band. If you keep them all together in one band, the report writer doesn't properly adjust for variable length subreports and text appears on top of other text.
Randy Hersom
President, Habilitation Software Inc.