After some time (maybe something like I close my browser session and reopen it a week later), reloading an existing Assistant tab changes/uses a URL like: https://kagi.com/assistant/9b109b17-c017-47d4-8f5a-c25fb6b23972
The page at this url shows:
This thread doesn't exist or you don't have access to it.
However, the thread can still be found via sidebar search and loads correctly with:
https://kagi.com/assistant/9b109b17-c017-47d4-8f5a-c25fb6b23972?branch=00000000-0000-4000-0000-000000000000
Opening /assistant/<thread-id> should either load the default/root branch automatically or redirect to the canonical URL including the correct branch parameter.