An index out of bounds error appears when adding multiple segments to a page variant then deleting them on the Choose Audience dialog of a page variant.

This is reproducible on the demo:
1- create a page
2- create a variant for that page
3- click choose audience
4- add a segment
5- add a second segment
6- delete that second segment
7- click save
The error banner will show after clicking save.

Additional Observation: If you add two segments (without deleting one) and click save, then re-open the dialog and delete one then click save again, then the issue does not occur. This only occurs when you add and delete while still having the dialog open, before clicking save.