Unclear "Invalid objectType" errors

Description

Today I got this kind of error:

 DEBUG[1] (/usr/share/fusiondirectory/include/class_filterLDAP.inc:get_list():165) - Invalid objectType given!: 'cn=testgroupsync,ou=groups,dc=ow2,dc=org'
Unknown element type specified!

The DNs showed in the message above vary depending on which section I browse (Users, Groups and Roles, Departements)

Then as I'm stuck there, I try to reload https://fusiondirectory.domain.com and get either the login form or the red message with inside "Cannot bind to LDAP" (I don't remember the exact sentence).

Distribution Name and Version

Debian 9.3

FusionDirectory Version

1.2-1

PHP version used

PHP 7.0 (fpm)

Origin of php packages

fusiondirectory repository

deb http://repos.fusiondirectory.org/fusiondirectory-releases/fusiondirectory-1.2/debian-jessie jessie main

fusiondirectory extra repository

deb http://repos.fusiondirectory.org/fusiondirectory-extra/debian-jessie jessie main

Click to see installed Packages:

ii  fusiondirectory                          1.2-1                                        all          Web Based LDAP Administration Program
ii  fusiondirectory-plugin-community         1.2-1                                        all          community plugin for FusionDirectory
ii  fusiondirectory-plugin-community-schema  1.2-1                                        all          LDAP schema for FusionDirectory community plugin
ii  fusiondirectory-plugin-dsa               1.2-1                                        all          dsa plugin for FusionDirectory
ii  fusiondirectory-plugin-dsa-schema        1.2-1                                        all          LDAP schema for FusionDirectory dsa plugin
ii  fusiondirectory-plugin-ldapdump          1.2-1                                        all          ldapdump plugin for FusionDirectory
ii  fusiondirectory-plugin-mail              1.2-1                                        all          base mail plugin for FusionDirectory
ii  fusiondirectory-plugin-mail-schema       1.2-1                                        all          LDAP schema for FusionDirectory mail plugin
ii  fusiondirectory-plugin-newsletter        1.2-1                                        all          newsletter plugin for FusionDirectory
ii  fusiondirectory-plugin-newsletter-schema 1.2-1                                        all          LDAP schema for FusionDirectory newsletter plugin
ii  fusiondirectory-plugin-personal          1.2-1                                        all          Personal plugin for FusionDirectory
ii  fusiondirectory-plugin-personal-schema   1.2-1                                        all          LDAP schema for FusionDirectory personal Plugin
ii  fusiondirectory-plugin-posix             1.2-1                                        all          posix account and group plugin for FusionDirectory
ii  fusiondirectory-plugin-webservice        1.2-1                                        all          webservice plugin for FusionDirectory
ii  fusiondirectory-plugin-webservice-schema 1.2-1                                        all          schema for the webservice plugin for FusionDirectory
ii  fusiondirectory-schema                   1.2-1                                        all          LDAP schema for FusionDirectory
ii  fusiondirectory-smarty3-acl-render       1.2-1                                        all          Provide FusionDirectory ACL based rendering for Smarty3

Steps to Reproduce

Cannot reproduce It happened suddendly The issue can be solved by cleaning the browser cache.