I got a similar exception!
I had no older saves (they were manually deleted), and can reproduce the error rather reliably:
- Start a new game. Don’t skip ahead. Other options are irrelevant.
- Talk with Sonya, Reina, Ryuji, the Ava crowds. Then let Morrison talk.
- Click the circular arrow twice. On the first time it’ll bring up the map as expected. On the second it triggers the exception.
From some quick websearch it seems that Ren’Py is trying to remove an element that doesn’t exist yet. If that’s correct odds are that this bug only triggers at the start.