Block not showing in post editor

Hello,

I've added the block using this template:
https://github.com/wpmetabox/library/tree/master/extensions/mb-blocks/hero

The block has registered, but it's not showing up in the post editor.

I think it's a Javascript error as I see this in console three times:

Uncaught TypeError: Cannot read property 'extend' of undefined
at Module.<anonymous> (blocks.min.js?ver=1.0.6:1)
at n (blocks.min.js?ver=1.0.6:1)
at blocks.min.js?ver=1.0.6:1
at blocks.min.js?ver=1.0.6:1

Any help would be appreciated! Thank you