Assets created on freshly forked off branches appear in their parent branches (BC cluster only)

Consider this scenario which works fine in non clustered business-central, but is broken in the business-cenral cluster

1. create project1
2. create branch1 from master
3. create branch2 from branch1
4. create dataObject1 on branch2

Expected: dataObject1 is on branch2 only, branch1 and master should be empty (this is how it works in plain git and also in non-clustered business-central)

Actual: dataObject1 is listed on branch2 AND ALSO when I switch on branch1

Sometimes this is not reproducible on the first try - just try repeating steps similar to 3 and 4 like so:
5. create branch3 from branch2
6. create some asset on the new branch -> the asset will appear on the previously created branches too.

In the end you'll see assets from the newly forked off branches visible on previously created branches and some assets are shown twice or more times.