Not sure it's wise to allow Moodle to update LDAP - although potentially it could. Most LDAP server admins that I have worked with would prefer that accounts be changed only on the LDAP server by authorized server admins.
Moodle requires username, first name, last name, and an EMail address on bulk uploads, but seems to change somethings with LDAP authentications ... one must have Country as well as City/State. Any of the moodle *required* fields for a profile that is NOT obtained from LDAP will result in the user being thrown into their profile. And, even though they don't know it, when they make/change entries, Moodle is attempting to make changes to LDAP - which is not setup.
So think your issue is related to configuration of LDAP in Moodle. At the bottom of that form there is the section on Data mapping.
First name = givenName
Surname = sn
EMail address = mail
City/Town = l
Country = c
Those attributes must exist in LDAP and could be different in your setup. Under each, there is a drop down list: Update Local
Think it wise to have that set to for each above to: on every login
Update external: set to never (which is default). Even if you set this one otherwise, LDAP server might reject changes unless it's setup to allow ... again ... don't think that wise at all.
You've not mentioned what your Moodle server's 'flavor' is ... Windows or Linux. If Linux, one could use ldapsearch from the command line to test access to the LDAP server (can't change/edit ... just query/test).
'spirit of sharing', Ken