Digging into generic error messages from Usage Reporting Plugin

After successfully enabling the Usage Reporting Plugin with masking disabled, the Errors page for our graph now shows some actual error messages, but others remain hidden behind a fairly generic message:

(5 Errored Traces Unavailable)

Is there anyway to get at the underlying error here? Plugin has been configured as follows:

     fieldLevelInstrumentation: 0.5,
     sendVariableValues: { all: true },
     sendErrors: { unmodified: true },
     sendUnexecutableOperationDocuments: true,