Cannot apply labels with script (possible bug with Asset Cache Server)

I made a simple little editor script to add/remove/clear labels on a set of objects. It seems to work fine (AssetDatabase.SetLabels()), except that when you begin to Play, Unity warns that the modified assets have not been re-imported since being modified.

The problem: when the asset is re-imported, either manually (by right-clicking) or through script (with AssetDatabase.ImportAsset()), the label changes are lost.

However, if I turn off "Use Cache Server", it is fine. Presumably, the optimization of getting imported assets from the cache server is ignoring the actual changes made locally to the asset's labels and just copying the asset from the server. That seems like a bug.

We definitely can't stop using the cache server, so any thoughts on workarounds?

 

I run into similar problem, where SetLabels was not working. What helped was calling:
AssetDatabase.ImportAsset(assetImporter.assetPath);
after SetLabels.