Gravatar issue looks to have resolved itself and it did appear to be at gravatar.com end of the business.
The Uncaught TypeError $ remains though.
I have played with GP Hooks and haven’t had any results. Disabled plugins to see if there is an issue there – there is, with the GP Hooks in the premium plugin of course.
Then I tried to just jam the script into the parent theme header.php file and the inspector error persists. I know what you mean about what is causing it, did my own digging here http://stackoverflow.com/questions/12343714/typeerror-is-not-a-function-when-calling-jquery-function
…but that doesn’t explain WHY it is happening. I have a hunch that it’s the version of jQuery that GP is using (it appears to be quite new). Maybe GTM code does not like it (strangely enough).
Update: I have done some more ‘digging’ and it appears to be the way the GTM code was constructed (was done by another dept, not ours) and they’ve obviously used some jQuery that conflicts with the one used in the GP theme. Here is the links to the stackoverflow posts:
http://stackoverflow.com/questions/22207431/jquery-being-loaded-into-gtm-js-from-google-tag-manager
http://stackoverflow.com/questions/33755168/jquery-and-google-tag-manager
Apparently the GTM script is serving jQuery v1.9.1 code. So I think that is where the issue may be. I have two questions for you Tom:
1) Can I change the version of jQuery that comes with GP
2) If I change the version of jQuery, will it cause errors with the theme or issues with the premium addons.