I think you'll have more luck asking this question of the Wordpress plugin developer. I "think" this is basically saying the Wordpress plugin isn't sending the correct info to Moodle.
I'm not a developer, but basing this post on the Moodle help page text, this line in particular:
Coding errors (or coding_exceptions) are problems that are probably caused by incorrect code. For example a plugin that does not communicate correctly with Moodle core.