I have been working on this historical entry for days at this point with little to no issue. For some reason, now when I edit the entry, and click "save changes," it deletes all changes I made. I do not know if this is just me, but it makes it impossible to easily proceed with the story of my world.
I do not know if you can reproduce this, but what I did was make a change to the timeline entry, and it deleted the changes when I clicked "save changes."
P.S. I am using the Euclid editor on spellcheck mode when this happens.
You cannot save correctly during spellcheck mode. Make sure to leave spellcheck mode once you are done editing and then let it save (press any keyboard key).