Just wanted to send a quick follow-up to this issue.
All tickets that went through support and were linked to the internal bug ticket had the same preceding error in the Designer console. This error showed the rootViewDefaultSize being undefined and resulted in the view not loading. Then when closing the view, the Unable to get the view config: View config is undefined error message would be displayed. The root cause was determined to be a race condition when opening views. A fix has been merged and will be available in 8.1.44.
If anyone is consistently seeing this issue, but have a different error unrelated to the rootViewDefaultSize the best course of action would be to reach out to support for further investigation.