Issue: Everyone is an admin 12.0.3

Nextcloud version: 12.0.3
Operating system and version: Ububtu 16.04 x64
Apache version: 2.4.18
PHP version: 7.0.22
MySQL: 14.14 Distrib 5.7.19

Is this the first time youve seen this error?: Yes

Can you reliably replicate it? Yes.

Issue: All users are able to add, disable, remove users. It seems as though all local users are admins no matter what group they are in. Even users in no group are admins. I did a hacky migration from owncloud 10.0.3 to owncloud 12.0.3 . I have been able to fix all issues except this one. Anyone willing to help me resolve this issue?