Jabele

I just did some further research. I updated the issue to be more generic since it does apply to basically anything.

This issue basically makes the spawn chunks useless.

In the world I uploaded I'm actually not sure about that. I thought the spawn chunk with the start ticket is always the chunk you spawn in. In my survival world however, I am sure of that, since I explicitly moved the worldspawn to this exact chunk (setworldspawn and reloaded) and got the same issue.
Also, in the described progress you use a command block to check whether the furnace changes states (in the commands provided the CookTime). This command block is loaded and it can access data of the furnace, so the furnace should be loaded as well.

I am not sure how this could help, however I did exactly as I described in a new world and uploaded it here. Tried to attach it directly but it's a bit too big. You should be able to see that furnace and nether portal is not only in the spawn chunks but actually in the chunk with the start ticket.

This is a duplicate of MCL-24439. The problem is that the Xbox Live Authentication servers are currently down (see https://support.xbox.com/en-US/xbox-live-status)

This is a duplicate of MCL-24439. The problem is that the Xbox Live Authentication servers are currently down (see https://support.xbox.com/en-US/xbox-live-status)

The problem is that the Xbox Live Authentication servers are currently down (see https://support.xbox.com/en-US/xbox-live-status)