I am running into an issue where the input button for image fields is not showing up in the cms, this occurs with 'image_advanced, 'single_image', 'image_upload'. Does not matter what the context is set to. There are no external styles being enqueued causing the field to be hidden. The input for type 'image' does show up.
This issue occurs in my code as well as the code supplied in the MB Blocks Demo.