Block not registered

[cena]

When opening a post where I'd previously used a SHE block, I now see this:

Plugin in active and installed. I also tried installing the Gutenberg plugin which didn't affect anything.

Strangely, it still seems to be working on the frontend:

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WP 6.1.1 TwentyTwelve TwentySeventeen Storefront SyntaxHighlighter: 3.6.2