Git Gatekeeper push doesn't work when adding new files

Reproduction:

• Create a branch
• Configure Plan Branch on it with Gatekeeper and push enabled
• Add a file to a branch, commit & push (important: do not modify any files: that works)
• Run Branch

Result: bamboo claims merge is correct, nothing appears on origin/master

At this point I'm no sure if it's relevant if merge is fast-forward -> test both scenarios