• This issue is blocking
  This is blocking publishing for MSBuild, and I suspect other repos that try to do any stable releases
• This issue is causing unreasonable pain

As seen in https://dev.azure.com/devdiv/DevDiv/_build/results?buildId=5670032&view=results, both the Unix and Windows manifests are reporting IsStable="true", but in the resulting merged manifest, the field is set to false. This causes us to not trigger the publishing code that creates isolated feeds for stable assets, resulting in errors to publish stable packages.

Need to fix the merged manifest creation so that it respects the existing property in the manifests.