Gutenberg 10.3.0 and Gutenslider 4.5 are not friends.

I upgraded to Gutenberg 10.3.0 the other day and tried to create a new Gutenslider. When I insert the block, I get a message ‘This block has encountered an error and cannot be previewed’.

If I save the page, return to it to edit it, where the Gutenslider block is I see the normal “Add media” ‘Add blank slide’ box, but when I click ‘Add media’ or ‘Add empty slide’ I get the same ‘This block has encountered an error and cannot be previewed.

I’ve tried this in my site’s fully-loaded config and in troubleshooting mode. The error occurs in either my theme or TwentyTwenty and happens when the Gutenberg plugin and the Gutenslider plugin are enabled at the same time — with none, any or all of my other plugins enabled.