Multiple Themes settings http and not https

Yes, it sounds like it.
Always start with the protocol that you intend to use. This will ensure that your content is properly replaced. If you switch between http and https you will get issues like the one you are describing.

I understand. But if you want to use your back-up to migrate from http to https or vice versa these problems will always occur.
Wouldn’t a warning be in order here? Preferably when you start the restore.

Migrating from http to https or the opposite should not be an issue.

The problem in your case is here

I should add that the site I was restoring in started out as http but in the back-up were the settings to make it https as was the site I backed up in.

Start with a site that is entirely using http or https. Make sure it is configured properly then import the archive.

I know what my problem is. I am merely asking for a warning when you are restoring a backup on a site that has a different protocol that points out the potential problems. Is this possible? Or should I request such changes/additions somewhere else?

Added a suggestion on Feedback site.

I redid the whole testing process and set the receiving site to the correct protocol before restore and no problems cropped up.

Thank you for describing what resolved it for you.