Posts Preview Issue – Shows in HTML(?)

Forgive me if this is naive question but I couldn’t figure out what to change to get this working correctly.

I’ve only got one post up and one in draft and in updating settings (changing the permalink format, user name, blog post layout to centered, etc), I went back to check the permalink using Edit and found the post preview now shows it in the format below rather than similar to the preview look. The published and preview pages still look fine, its just using the edit that is now near-impossible for me.

There was something that warned me in a setting about altering the theme or something but I thought I exited it appropriately without making any changes. Now (of course), I can’t find where that was at.

Thanks in advance.
TM10

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<!– wp:paragraph –>
<p>After a few years of ups and downs I was so looking forward to bringing my sons to Europe and meeting up with my sister in Italy.<br><br>I watched intently as 4 people tested positive for Coronavirus in the Milan and Bologna region. While we were staying in Rome, I had planned a special surprise for the boys to see the super-car dynamos Ferrari, Pagani, and Lamborghini. A day or two later the number jumped to 150 positive cases. </p>
<!– /wp:paragraph –>

The page I need help with: [log in to see the link]