I brought your module into a new file, deleted the dimensions, selected all walls, applied the exterior dimensioning tool and voila...
same problem! The left side, having composite walls, did not include interior partitions in the dimension string, while the right side still worked correctly.
Are you on INT or US version? I can't think of what other differences in settings or WE that could be the cause.
ArchiCAD 12; Artlantis Studio 2
MacBook Pro 2.4 Core2Duo, 2GB, OSX(10.5) and XPpro(SP3)