EditorsKit + Using

Hello,
We are using the “EditorsKit” Plugin on our homepage kevnana.de, but it seems since the last update 1.31.3 (or maybe a few before) we have the problem, that we cannot go into the editor if the post includes Page Breaks (so multiple pages in one post). It automatically shows an error with an error code like this:

TypeError: Cannot read property 'family' of undefined
    at https://kevnana.de/wp-content/plugins/block-options/build/index.js?ver=1627292572:16:388063
    at we (https://kevnana.de/wp-includes/js/dist/vendor/react-dom.min.js?ver=16.13.1:84:293)
    at zj (https://kevnana.de/wp-includes/js/dist/vendor/react-dom.min.js?ver=16.13.1:226:496)
    at Th (https://kevnana.de/wp-includes/js/dist/vendor/react-dom.min.js?ver=16.13.1:152:223)
    at tj (https://kevnana.de/wp-includes/js/dist/vendor/react-dom.min.js?ver=16.13.1:152:152)
    at Te (https://kevnana.de/wp-includes/js/dist/vendor/react-dom.min.js?ver=16.13.1:146:151)
    at https://kevnana.de/wp-includes/js/dist/vendor/react-dom.min.js?ver=16.13.1:61:68
    at unstable_runWithPriority (https://kevnana.de/wp-includes/js/dist/vendor/react.min.js?ver=16.13.1:25:260)
    at Da (https://kevnana.de/wp-includes/js/dist/vendor/react-dom.min.js?ver=16.13.1:60:280)
    at Pg (https://kevnana.de/wp-includes/js/dist/vendor/react-dom.min.js?ver=16.13.1:61:14)

And also, if we go into a new post (without page breaks yet), open on the left side the block menu and even only hover with the mouse over the “Page Break” Button, automatically the editor closes with similar error messages.

I think the button appeared for the first time, when also the black green “Library” Button appeared at the top of the editor.

We are using WordPress 5.8 in German. Even the editor crashes in the backend (which makes editing pages with Page Break blocks impossible), in the frontend everything looks fine.

Are there any bug fixes for this? Or is it possible to download the plugin in an older version (1.31.0? 1.30.0?)

With kind regards,
Kevin Lang

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