Unable to change avatar on the personal pages after adding the LDAP / AD integration

Nextcloud version (eg, 10.0.2): 12.0.3
Operating system and version (eg, Ubuntu 16.04): Ubuntu Server 16.04.03
Apache or nginx version (eg, Apache 2.4.25): Apache 2.4.18-2ubuntu3.5
PHP version (eg, 5.6): 7.0
Is this the first time you’ve seen this error?: Yes

Added the LDAP / AD integration, and everything works great.

The “User Authentication with LDAP” chapter of the Server Administration Manual states: “If the jpegPhoto or thumbnailPhoto attribute is not set or empty, then users can upload and manage their avatars on their Nextcloud Personal pages”. Both attributes are unset in AD, but I am still unable to change the avatar in Nextcloud personal pages.