Pull-request on updated community 4.12.4 ERROR Rules

Hello,
Updated my RC from 4.10.1 to 4.12.4, and now, when doing pull-request, and adding the reviewers, so clicking on pull-request, I get this:

“Error creating pull request: review_members: Errors: rules: Missing value”

Obs:seems like there is no rule for reviewer, but I cannot change due to community version

What do I do?!

2018-07-18 16:30:46.164 INFO [rhodecode.lib.auth] user <AuthUser(‘id:4[maiquelb] ip:192.168.3.6 auth:True’)> authenticating with:RHODECODE_AUTH IS authenticated on func RepoPullRequestsView:pull_request_create
2018-07-18 16:30:46.244 ERROR [rhodecode.apps.repository.views.repo_pull_requests] Error creating pull request: review_members: Errors:
rules: Missing value
Traceback (most recent call last):
File “/opt/rhodecode/store/p9vr3b65srfrkr4gbag23mpcdkk0xy6w-python2.7-rhodecode-enterprise-ce-4.12.4/lib/python2.7/site-packages/rhodecode/apps/repository/views/repo_pull_requests.py”, line 799, in pull_request_create
_form = form.to_python(controls)
File “/opt/rhodecode/store/kvwhp79i5dck97jpdgwcglv6xbjbza90-python2.7-FormEncode-1.2.4/lib/python2.7/site-packages/formencode/api.py”, line 419, in to_python
value = tp(value, state)
File “/opt/rhodecode/store/kvwhp79i5dck97jpdgwcglv6xbjbza90-python2.7-FormEncode-1.2.4/lib/python2.7/site-packages/formencode/schema.py”, line 196, in _to_python
value_dict, state, error_dict=errors)
Invalid: review_members: Errors:
rules: Missing value

follow here: https://issues.rhodecode.com/issues/5491