Warning: Illegal string offset 'appears' in spambot_sfs_request() error when creating an account

Problem/Motivation

Just got the following error when signing up for an account on a local site during testing:
Warning: Illegal string offset 'appears' in spambot_sfs_request() (line 387 of /var/www/vhosts/prolificnorth.co.uk/www/sites/all/modules/contrib/spambot/spambot.module).

I'm currently testing logintoboggan and it's email verification setting. Using the latest version of Drupal 7.73 on php 7.2