Mac causes sleep wake loop on monitor

I have a "New Macbook" (April 2015) connected to my LG 27EA83 monitor via HDMI. In Energy Saver, it's configured to turn off the display after 10 minutes.

After this happens, the monitor goes into a sleep/wake loop where it awakens every 22 seconds or so, making an annoying beep and not saving energy.

You can see the behavior in this video.

I can turn off the monitor and the loop stops, but that's not a good solution because it causes trouble with the detected resolution when resuming, and because an action that happens implicitly due to an idle timeout (display turned off after 10 minutes) shouldn't require an explicit action to avoid ugly behavior.

I've used this monitor with several other Windows-based laptops on the same HDMI interface without trouble, so the issue is necessarily due to the Mac's hardware or software.

I appreciate any suggestions you might offer to troubleshoot or correct the issue.