Description

In function updateAttributes(attributes) in const updateFootnotes called in the footnote block,

Recursive calls to the updateAttributes function

        if (Array.isArray(value)) {
          attributes[key] = value.map(updateAttributes);
          continue;
        }

If there is an attribute of an array of strings at this time

                imgSizes : {
                    type: "array",
                    items: {
                        type: "string"
                    },
                    default: []
                },

For example, the string "1024x768" is converted to {0: "1", 1: "0", 2: "2", 3: "4", 4: "x", 5: "7", 6: "6", 7: "8"} and an error occurs

Step-by-step reproduction instructions

This happens when you manipulate the footnote block in the editor.

This happens in blocks that use an array of strings in the attributes, but does not seem to be used in the core block.

Screenshots, screen recording, code snippet

Environment info

WordPress 6.3 RC2

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

No