I'm using a Table Row to Variable Loop to go through a table. It is possible, that the table is empty. The Table Row to Variable Loop Node cannot process empty tables, so I use an Empty Table Switch as a check. If the table isn't not empty, everything is fine. If it is empty, the switch correctly x-es out the top output and uses to bottom one, but somehow the loop end wants to be executed and the stream ends without finishing and following error message:
Can you send me a screenshot of your workflow? Alternativey, what kind of loop end node are you using? I attempted to reproduce your problem, but so far it works for me.
I think this issue was actually fixed in KNIME 2.8.1, which we pushed out just hours ago (and this is why I couldn't reproduce the problem). Would you mind updating and letting me know if the patch does indeed fix things up for you?