Ooh, this is a neat podcast niche that I'll probably enjoy! If you're taking suggestion of public postmortems to talk about I recommend Github's 2018 outage [1,2] caused by a network partition.

[1] https://github.blog/2018-10-21-october21-incident-report/

[2] https://github.blog/2018-10-30-oct21-post-incident-analysis/