petition with attributes populated from EnvSource will not validate

When a self-signup enrollment flow has an attached Org Identity Source of type EnvSource and has enrollment attributes that are configured to use values from the environment as default values the submitted petition cannot be validated and returns "Please recheck the highlighted fields".

If the configuration is changed so that default values for the form are not pulled from the environment but then the user enters values by hand into the form then the petition is validated and enrollment continues.

In the first case when the default values are pulled from the environment and submission of the form fails the submitted POST includes 

data[CoPetition][id]: 62
data[CoPetition][token]: b8bd8d86ce30421716045b58090519b8aa0627e0
data[CoPetition][token]: b8bd8d86ce30421716045b58090519b8aa0627e0
data[EnrolleeCoPerson][Name][34][co_enrollment_attribute_id]:
data[EnrolleeCoPerson][Name][34][type]:
data[EnrolleeCoPerson][Name][34][language]:
data[EnrolleeCoPerson][Name][34][primary_name]:
data[EnrolleeCoPerson][EmailAddress][33][co_enrollment_attribute_id]: skoranda@gmail.com
data[EnrolleeCoPerson][EmailAddress][33][type]: skoranda@gmail.com
data[EnrolleeCoPerson][EmailAddress][33][verified]: skoranda@gmail.com
data[EnrolleeCoPerson][CoGroupMember][46][co_group_id]: 4
data[EnrolleeCoPerson][CoGroupMember][46][member]: 1
data[EnrolleeCoPerson][CoGroupMember][46][owner]: 0
data[EnrolleeCoPerson][CoGroupMember][46][co_enrollment_attribute_id]: 46
data[EnrolleeCoPersonRole][cou_id]: 1
data[EnrolleeCoPerson][Name][34][honorific]:
data[EnrolleeCoPerson][Name][34][given]: Donald
data[EnrolleeCoPerson][Name][34][middle]:
data[EnrolleeCoPerson][Name][34][family]: Koranda
data[EnrolleeCoPerson][Name][34][suffix]:
data[EnrolleeCoPerson][EmailAddress][33][mail]: skoranda@gmail.com
data[EnrolleeCoPersonRole][affiliation]: staff
data[EnrolleeCoPersonRole][title]:
data[EnrolleeOrgIdentity][o]:

Contrast that with the same information sent in the POST when default values are not pulled from the environment and instead the user enters them into the form:

data[CoPetition][id]: 55
data[CoPetition][token]: 65edde7abc6c143d333cfc0a7def9ff2b6a682ca
data[CoPetition][token]: 65edde7abc6c143d333cfc0a7def9ff2b6a682ca
data[EnrolleeCoPerson][Name][34][co_enrollment_attribute_id]: 34
data[EnrolleeCoPerson][Name][34][type]: preferred
data[EnrolleeCoPerson][Name][34][language]:
data[EnrolleeCoPerson][Name][34][primary_name]: 0
data[EnrolleeCoPerson][EmailAddress][33][co_enrollment_attribute_id]: 33
data[EnrolleeCoPerson][EmailAddress][33][type]: preferred
data[EnrolleeCoPerson][EmailAddress][33][verified]: 0
data[EnrolleeCoPerson][CoGroupMember][46][co_group_id]: 4
data[EnrolleeCoPerson][CoGroupMember][46][member]: 1
data[EnrolleeCoPerson][CoGroupMember][46][owner]: 0
data[EnrolleeCoPerson][CoGroupMember][46][co_enrollment_attribute_id]: 46
data[EnrolleeCoPersonRole][cou_id]: 1
data[EnrolleeCoPerson][Name][34][honorific]:
data[EnrolleeCoPerson][Name][34][given]: Donald
data[EnrolleeCoPerson][Name][34][middle]:
data[EnrolleeCoPerson][Name][34][family]: Koranda
data[EnrolleeCoPerson][Name][34][suffix]:
data[EnrolleeCoPerson][EmailAddress][33][mail]: skoranda@gmail.com
data[EnrolleeCoPersonRole][affiliation]: staff
data[EnrolleeCoPersonRole][title]:
data[EnrolleeOrgIdentity][o]:

This was demonstrated with commit a819e6 from develop.