database relay suffix cn=outlook,dc=stanford,dc=edu relay cn=people,dc=stanford,dc=edu massage
Try using rwm- directives explicitly instead of the implicit suffixmassage/map/rewrite/relay etc. directives; I think the process of deprecation there might be getting in your way. Perhaps:
# "cn=outlook" input, "cn=outlook" output, data hosted in "cn=people" below database relay suffix cn=outlook,dc=stanford,dc=edu overlay rwm rwm-suffixmassage cn=people,dc=stanford,dc=edu
# define cn=people here ("dc=stanford,dc=edu" should do)