The editor has encountered an unexpected error

Hi! I updated to the latest version of WordPress a couple of hours ago. I updated a few blog posts, no problem, but then when I tried to update the one included in this post I got a white screen with just a message:

The editor has encountered an unexpected error.

Then three options “attempt recovery”, “copy post text” and “copy error”.

This is what I get when I copy the error. When I click the “attempt recovery” nothing happens.

TypeError: Cannot read property '0' of undefined
    at https://c0.wp.com/p/jetpack/9.9.1/_inc/blocks/editor.js:31:127448
    at Array.map (<anonymous>)
    at https://c0.wp.com/p/jetpack/9.9.1/_inc/blocks/editor.js:31:127351
    at Array.map (<anonymous>)
    at n.value (https://c0.wp.com/p/jetpack/9.9.1/_inc/blocks/editor.js:31:127289)
    at https://c0.wp.com/c/5.8/wp-includes/js/dist/element.min.js:2:8150
    at V (https://c0.wp.com/c/5.8/wp-includes/js/dist/element.min.js:2:8164)
    at A (https://c0.wp.com/c/5.8/wp-includes/js/dist/element.min.js:2:9174)
    at D (https://c0.wp.com/c/5.8/wp-includes/js/dist/element.min.js:2:8629)
    at V (https://c0.wp.com/c/5.8/wp-includes/js/dist/element.min.js:2:7940)

Can anyone shed some light on this and how to fix it? I vaguely remember it happened to me once before a couple of years ago, but I can’t for the life of me remember how I resolved it. Thank you for your time and help.

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