multi-stage pipeline using dotnet pack fails around versioning

I am trying to get one pipeline to both build and test my code, and in another stage to pack and push a nuget package.

name: $(SourceBranchName)-$(Date:yyyyMMdd)$(Rev:.r)trigger:  branches:    include:       - 'master'  paths:    exclude:      - deploy/*stages:# Build, test and package for deployment- template: deploy/build/stage.yaml- template: deploy/build/nuget.yaml

The pipeline fails in the last stage, on packing the nuget file.

##[error]Could not find version number data in the following environment variable: BUILD_BUILDNUMBER. The value of the variable should contain a substring with the following formats: X.Y.Z or X.Y.Z.A where A, X, Y, and Z are positive integers.

I understand that in the outer yaml file where the "name" is part of the underlying versioning scheme, is part of the error here. But can I somehow in my nuget.yaml override the outer "name" attribute ?

In the nuget.yaml file I am doing this (sorry for the formatting)

variables:    buildConfiguration: 'Release'    majorMinorVersion: 1.2    # semanticVersion counter is automatically incremented by one in each execution of pipeline    # second parameter is seed value to reset to every time the referenced majorMinorVersion is changed    semanticVersion: $[counter(variables['majorMinorVersion'], 0)]     - task: DotNetCoreCLI@2        displayName: 'dotnet pack'        inputs:          command: pack          projects: src/**/*.csproj          versioningScheme: byBuildNumber

The nuget.yaml file runs fine by itself when it's not part of a a multi-stage pipeline.