The change in #18995 includes a conditional to User#visible_environments to return envs with no match to associated locations and organizations:

https://github.com/theforeman/foreman/commit/f4b7c52fe4012592656c0fcd56bcdd09e3ea246a#diff-4676c008b11a5480d73d4a6de01e45b9R410

This uses the condition User.current.admin, but it should use User.current.admin?, which is the method that returns inherited admin flags. The #admin method is the attribute, so this would only work for admin users with the flag explicitly set.