Fatal error: Cannot use string offset as an array

[recedo]

Using version 3.0.1 of plugin and Gravity Forms 1.9.2

Trying to map fields to custom taxonomies. A dropdown works fine, as do checkboxes but when I try to add a single text field to map to my custom tags taxonomy I get the following error on frontend and backend when trying to access the form (with and without advanced UI selected);

Fatal error: Cannot use string offset as an array in /home/XXX/public_html/wp-content/plugins/gravity-forms-custom-post-types/gfcptaddonbase.php on line 301

I notice that there was an update to gfcptaddonbase.php 10 days ago so tried that and have the same error, just moved to line 241.