Problem/Motivation
The solution for this issue #2561619: Drupal Ajax objects and settings grows endlessly lead previously to errors in contrib modules like the one we fixed here #2673824: Views JS passing wrong type of object to Drupal.ajax.
But due to other possible errors in contrib that issue was rolled back in 8.0.x, but I found a related error that breaks in 8.1.x due to that change, you can see it here: https://github.com/dpi/courier/issues/21 maybe in other modules.