AttributeError at /group/5

'ManyRelatedManager' object has no attribute 'query'

Request Method: 	GET
Request URL: 	https://biscuit.boltenheide.de/group/5
Django Version: 	2.2.4
Exception Type: 	AttributeError
Exception Value: 	

'ManyRelatedManager' object has no attribute 'query'

Exception Location: 	/srv/biscuit/lib/python3.7/site-packages/django_tables2/data.py in ordering, line 186
Python Executable: 	/usr/bin/uwsgi-core
Python Version: 	3.7.3
Python Path: 	

['.',
 '',
 '/srv/biscuit/lib/python37.zip',
 '/srv/biscuit/lib/python3.7',
 '/srv/biscuit/lib/python3.7/lib-dynload',
 '/usr/lib/python3.7',
 '/srv/biscuit/lib/python3.7/site-packages',
 '/usr/src/BiscuIT-ng/apps/official/BiscuIT-App-Exlibris',
 '/usr/src/BiscuIT-ng/apps/official/BiscuIT-App-SchILD-NRW',
 '/usr/src/BiscuIT-ng',
 '/usr/src/BiscuIT-ng/apps/official/BiscuIT-App-Chronos',
 '/usr/src/BiscuIT-ng/apps/official/BiscuIT-App-Untis']