Update library and load subtree fails in plugin

[brollb]

I recently encountered a bug when I try to update a library using core.updateLibrary then core.loadSubTree(this.rootNode):

Before I continue, the logic containing the core.loadSubTree is in a project migration which automatically updates the project data based on some recent update.

This is what I have checked out so far:

• I have confirmed that the individual logic is correct; commenting out the library update or subsequent code both is successful.
• Saving between the steps (not ideal) still results in the same error.
• When running the library update code in isolation, I have confirmed the library root hash changes.
• The node causing the issue was created manually using the default webgme UI so I expect it to be well-formed in both cases.
• Running the library update and then re-running the plugin to only run the migration works.
• Previously, I was using the client to update the library but this often resulted in the branch forking since the client and plugin were making concurrent edits. Trying to merge these concurrent changes results in the following error: