I've attached a 2.1.1 test document that crashes in 2.2 beta 1986 when I click into either of the two TOCs at the top of the page and turn off Include as PDF Bookmark. Doing the same thing doesn't crash in 2.1.1.
toc test 3.afpub
Affinity Publisher 2 Beta-2023-09-06-135010.ips
If I deselect Heading 1 in the TOC panel's style list for TOC 2 before clicking Include as PDF Bookmark it won't crash. It does in my real document and I'm still trying to figure out why it only crashes in that one.
The reason I want to turn off Include as PDF Bookmark for the secondary TOCs is that if TOC 2 has Heading 1 turned off, then Heading 2's PDF bookmark won't be nested under Heading 1. So any book with multiple TOCs needs to turn this off or it will break the PDF bookmark hierarchy.