CK version 4.3.3 in ( Firefox | Chrome ) in Windows. Paste text with a ] in it, and an error shows in the console. Intermittent.
From FIrefox:
Error: Syntax error, unrecognized expression: ]
...break;q=a}return s},m.error=function(a){throw new Error("Syntax error, unrecogni...
From Chrome:
Uncaught Error: Syntax error, unrecognized expression: .
See attached screenshot for the rest of Chrome's report.
That callstack shows that the
That callstack shows that the error is in a jQuery function called by Drupal, so you should look for help in the Drupal forums about what that function does.