I just did some more testing and found what breaks it for me.

https://i.imgur.com/SAbrkQe.png

If I just set a mode for the timeline itself, it loads just as it should, however, the moment I add a mode to the Create Post block, it breaks the loading for me.

This is what I get when Create Post block has any mode set other than off: https://i.imgur.com/5pftgWS.png
This is what I get when I set the mode for Create Post to off but the timeline block still has a mode enabled: https://i.imgur.com/91CJWzm.png