Question tags are short phrases added at the end of a statement to transform it into a question or to seek confirmation or agreement from the listener.
The following example show that native speakers do not always use the correct form of ‘BE’:
In the English Grammar Profile, C1 point 33 in QUESTIONS/tags is defined as:
affirmative and negative forms of question tags with ‘there’ + ‘be’
Here’s an iWeb corpus search for:
, _VB there ?
1 , IS THERE? 1657
2 , ARE THERE? 174
3 , WAS THERE? 118
, _VB _XX there ?
1 , ISN’T THERE? 585
2 , AREN’T THERE? 140
3 , WASN’T THERE? 77
iWeb won’t allow checking the actual results, so we move to COCA:
3 2019 TV Les Misérables
And she’s your granddaughter?
Well, she takes after her mother’s side.