Searching for user with complete name in "Full Name" field doesn't work on LDAP

From a customer: "When searching for a user using the "Full Name" field, it will generate results if you use only their first or last name. However, if you use their full name, it does not return anything. This issue affects 2.5.2 and 2.5.4.

I have Confluence set up with LDAP integration (meaning, my user directory is generated from the Active Directory). This feature worked correctly in 2.4.2.

This bug is holding back our deployment of Confluence to production, so we would appreciate a fix ASAP."

Confirmed on 2.6-dev - this only happens when using LDAP