Encountered this issue as well, appears to be because I renamed my Hub model after mapping to it in the Supply Chain Model. I was able to resolve the issue by going to Model Setting > Actions > Import Data Sources, selecting the Source (the Imports column should list which one points to 9.1 Import Historic Volumes), then editing it to point to the proper Model. Since I renamed the model, it threw an error message because it couldn't find the original source, but after editing it, the import ran successfully! Thanks to all who logged suggestions before, hopefully this resolves the issue for anyone going forward!
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