A whole host of crashes are manifesting as "access violations", and they are related to bones (this time)! Not skellington bones, but think objects that are dynamic, have some wobbles or physics -- hats with plumes, or beastmen banners for eg. So they are likely a big part of the Chaos Wastes crashes (when it comes to banners and the likes).

Also the SOTT Lingering Blackvenom issue fixed in this hotfix could be the cause of some of them, too.

Not so much, the hotfix we have here included fixes made before release which didn't make the cut (such as grudge marks icons) as well as some critical fixes for stability. We'll get around to fixing Sienna's dot-problems for sure, and we appreciate for our Sienna crowd they're super important, but getting the game to remain functional when someone changes their hat or meets a bannerboi is priority.