500 on Merge Pull Request

When the following options are set on a GITEA branch our Merges for Pull Requests fail with a 500 error:
Branch Protection: Enabled with Disable Push
Required Approvals: 1
Team or user that will be reviewing is defined in the whitelisted reviewers

New to this whole raising an issue thing, so give me a shout for any other information you need.

Many thanks,

David

A little more information:
Built from latest Docker Image
GITEA Version: 1.11.0+dev-393-g95a57394a
GIT Version: 2.22.0
DB: Postgres 9.6

Further information:
2019/12/13 14:12:12 …s/context/context.go:138:HTML() [D] Template: status/500
2019/12/13 14:12:12 routers/repo/pull.go:711:MergePullRequest() [E] Merge: git push: remote: Gitea: Internal Server Error
remote: invalid character ‘<’ looking for beginning of value
To /data/git/repositories/test/test.git
! [remote rejected] base -> master (pre-receive hook declined)
error: failed to push some refs to ‘/data/git/repositories/test/test.git’

2019-12-13 14_17_58-Internal Server Error