When using EM Lightning Sandbox Beta clicking on any related list "A component error has occurred" error message displays.
This issue occurs when the affected users' language is set other than English and the Google Chrome built-in translator is turned on.
This is a known Salesforce issue that currently doesn't have a solution.
The reason for this is that when Chrome translates the page to another language, a font is applied to the text that displays the text in the other language. When the user clicks directly on the translated text, the handleTabClick method does not correctly capture the clicked event on the tab. It instead captures the event on the font. If someone clicks on the tab but slightly off of the text, the tab displays as normal. There is no tab information associated with the font applied by the translation, therefore Salesforce throws an error that says it cannot read the properties of undefined.
Turn off the Google Chrome built-in translator.