Deleting C or Final mailing for A/B test makes report on A and B segments unviewable

If you create and A/B test, send the A & B segments and then delete the C or Final segment from Draft and Unscheduled Mailings, you can no longer view the mailing report for the A/B test. The mailing report URL just shows a blank page with header and footer.

I think it is probably not that uncommon an occurrence for someone to create an A/B test and later need to make a small change to the final version before sending it. That's easy enough to do by re-using one of the mailings and excluding the A and B mailings from your recipients. However, you will probably delete the C mailing from the unscheduled list at this point and then no longer be able to view the original A/B mailing report.

I'm testing on 5.28.4. This happens with both Mosaico and traditional mailings.