Error when interacting with a paragraph block

[versatilehuman]

Describe the bug
Gutenberg 4.0.0 & 4.1 RC2: Any time a paragraph block is clicked, this error appears: "The editor has encountered an unexpected error." This happens in any post type using the Gutenberg editor. It occurs with new and existing posts.

To Reproduce
Steps to reproduce the behavior:

1. Click "Posts"
2. Click "Add New" or click "Edit" on an existing post
3. Click on any paragraph block or create new paragraph block
4. See error

Expected behavior
Being able to edit/add paragraph blocks.

Screenshots

Additional context

• Problem present in Gutenberg 4.0.0 & 4.1 RC2, but not 3.9.0 or previous.
• WordPress 4.9.8
• Windows 7 64-bit
• Chrome 69.0.3497.100
• Problem present in Gutenberg 4.0.0, but not 3.9.0 or previous versions.
• Problem persists even after deactivating all plugins

[versatilehuman]

Is there any further information I can pull to help figure this out?

Same Error in IE 11.0.9600.19129:

TypeError: Object doesn't support property or method 'find'
   at Anonymous function (/wp-content/plugins/gutenberg/build/components/index.js?ver=1540390037:37:248589)
   at yh (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:95:428)
   at lg (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:120:82)
   at mg (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:120:384)
   at gc (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:127:200)
   at vb (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:126:230)
   at ub (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:126:65)
   at wg (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:137:182)
   at Ze (
/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:41:24)

Error in Chrome 69.0.3497.100:

TypeError: r.find is not a function
    at /wp-content/plugins/gutenberg/build/components/index.js?ver=1540390037:37:248593
    at yh (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:95:430)
    at lg (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:120:88)
    at mg (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:120:386)
    at gc (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:127:202)
    at vb (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:126:230)
    at ub (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:126:65)
    at wg (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:137:182)
    at Ze (/wp-content/plugins/gutenberg/vendor/react-dom.min.82e21c65.js:41:24)

[versatilehuman]

Updated to reflect that the issue only occurs with paragraph blocks.

[versatilehuman]

Resolved.

Was using this empty add_theme_support hack to remove font size options.

function fpdcc_gutenberg_disable_all_colors() {
	add_theme_support( 'editor-font-sizes' );
}
add_action( 'after_setup_theme', 'fpdcc_gutenberg_disable_all_colors' );