Using branch plan dependency, branch plan name is checked instead of repository branch name.

If the branch plan display name is different than the parent branch plan, the dependency is not triggered despite using the same branch from the same repository.

Point of improvement would be documenting this better to prevent confusion. For instance, updating the description on the Enable dependencies for all branches of this plan option:

Dependencies are triggered for branches only if there is a branch branch plan with the same name display name within the dependent plan