Hi Jim,
Thanks for sharing your experience with us.
I did a test at my end with the following steps:
1.Cretae a document library and add a Managed Metadata column in it.
2.Create a view of the library to be grouped by the Managed Metadata column.
(I didn't add a custom content type in the library as I'm not sure how the custom content type is configured on your side)
3.Create a folder in the library.
Then when I upload documents in the library via the Upload button in the ribbon, I can assign the Metadata value to it.
When I upload documents in the library by dragging and dropping, I can assign the Metadata value to the documents via selecting the document>in the details pane, click Edit all>it has the option for
Metadata to select a Metadata value.
Without the content type added in the library, it seems the issue cannot be reproduced.
It seems the issue is related to the content type you configured. To check if it is a bug and check if we can reproduce the issue, could you help providing the following information?
Regarding "Configure a Document Library to allow one custom Content Type which includes a Managed Metadata column." Please let us know how you configure the content type including the
metadata column in the library.
Could you share your steps with us?
Or you can capture some screenshots of the settings page for the content type.
This will helps us create a test environment and try to reproduce the issue.
Regards,
Tina