Happens when you click on "add and condition"
seems to fail here:
Creating this here since the segment widget is in core. The feature still seems to work without any issues so far so if it's not an easy fix we might just ignore it.
That was a real though one to debug. It is indeed triggered by the
matches method of an element. But in that special case the element seems to be the form element, which contains the segment editor. The segment editor itself contains an element with the name
matches, which thus is part of the form. That causes
el.matches not to contain the actual method it should be, but to hold the
matches form element instead. That causes the error as it tries to use the form element as callback later...
A possible fix would be to rename the form field or to remove it's name completely.