Hello Olga,
1 – Totally understood! I did see that this feature is in beta, so I guess it is normal to see bugs… Thank you for taking the time to investigate and solve them!
2 – In my case, the warning appears each time I try to close the tab of the header builder. Even if I don’t change anything and try to close it, the message appears. And if I have done some change and saved it correctly, the message appears too. I use Chrome browser if it helps. This is not my screenshot but the message is identical: https://i.stack.imgur.com/x5blG.png
When it appears I simply close it and the tab too, then I check the page where that header appears and I see that the change was correctly done so I don’t know why it appears.
Thank you!