In a Direct Transfer activity, the Table field under Source Connection is supposed to be optional. However, starting in LEI 8.5.x, if this field is left blank, the document cannot be saved. The action fails with the following error:
"Error: The source metadata must contain a value"
This issue is under investigation, and is being tracked as SPR MJON7TQNNV.
Resolving the problem
To work around the issue, place any value in the Source Connection's Table field. So long as there is any value in there at all, the error will not appear, and the document can be saved normally. (The value will not have any effect on the activity).
For best results, use a space, to avoid having a potentially confusing value in the field.