Ok, I updated again and tried messing around with it. Here's what I found!
Creating a new Source Clone of anything works fine without any issues. So the problem for me is only existing Source Clones (which I only have of scenes).
Going into the Properties of any broken Source Clone and changing a setting doesn't do anything. If I click "OK" to close the properties, the Source Clones remain borken.
However, if I simply open the Properties and click "Cancel", the Source Clone fixes itself! I went through and tried it with every one of my Source Clones, and it worked with all of them.
Unfortunately, closing OBS and relaunching it breaks them all again, but the new ones all remain working.
Essentially, this newest update isn't really backwards compatible without some effort. To avoid issues, I would need to recreate all of my Source Clones.
Hope this helps! For now I'm going to roll back again, but let me know if you want me to give anything else a try.
Thanks!