When using the Re-Index Tree functionality in the Content Editor, the selected item and its descendants fail to be re-indexed successfully. This is caused by the following exception thrown from the Crawler<T>.RefreshFromRoot(IProviderUpdateContext, Indexable, IndexingOptions, CancellationToken) method:
(ArgumentException) indexableStartingPoint Sitecore.ContentSearch.SitecoreIndexableItem is not an instance of Sitecore.Commerce.Engine.Connect.Search.Models.CommerceCatalogIndexableItem
To resolve the issue, download and install the patch found on this page:
https://github.com/SitecoreSupport/Sitecore.Support.39467/releases