Hey there!
I’m using this magnificent plugin to easily create a custom post type for my company and I ran into a snag. It’s fixed now thanks to this post: https://piklist.com/support/topic/error-when-replacing-editor-and-specifying-scope-as-post/
But I’m wondering why it hasn’t been fixed in the plugin.
I use WordPress 4.7.2 and Piklist 0.9.9.9 …. with the default theme 2017 active and no other plugins on my .dev localhost.

I made the following change to the class-piklist-form.php:

// array_push($return, $object->$field['field'] ? $object->$field['field'] : $field['value']);
array_push($return, $object->{$field['field']} ? $object->{$field['field']} : $field['value']);

The fix works on my dev station in Php versions 5.x and 7.x.

Hope this helps anyone else scratching their heads.

Cheers!