That is a report of a complex internal MacOS issue, where the daemon (always running task) that controls all other watchdog timers stopped responding. Watchdog timers are set when a task will be completed in the future, but far too long to sit and wait for the results.
That is unlikely to be caused directly by your external display.
But it could be caused by invasive added third-party software.
Consider downloading and running this little "discovery" utility, Etrecheck. It changes NOTHING. Etrecheck was developed by a senior contributor here, and uses mostly system calls and simple tests to collect often-needed information.
it contains little tests for speeds of devices, CPU utilization, memory usage, energy usage and a digest of recent problems, in one easy to use package. it does not even need to be Installed. Because less can be learned when your Mac is running great, best time to run is when your problems are actually occurring, if possible.
if you follow the directions faithfully, its report (pre-laundered of all personally-identifiable information) can be "Shared" to the System ClipBoard, then Pasted into an ‘Additional Text’ window in a reply on the forums.
Use Etrecheck Pro for free:
http://Etrecheck.com
The amount of data you get can be daunting. If you POST your report, some Readers here are willing to look over those reports, and can provide valuable insights.
then start a reply on the forums, click the 'Additional text' icon, and PASTE
