Random code injected when using custom path for shortcodes

[aptonline]

I've recently setup a custom path in Shortcodes-core for some shortcodes that came bundled with a theme (HotDoy) so I followed the example path given and added them here: /user/custom/shortcodes/

Upon saving I get the following injected into the header of EVERY page including the admin backend and front end:

Fetch Failed: Bud1 tled funtitled folderIlocblob;(������untitled folderlg1Scompuntitled foldermoDDblob�t��Auntitled foldermodDblob�t��Auntitled folderph1ScompVimeoShortcode.phpIlocblobI�������� @� @� @� @E DSDB � @� @� @{"status":"success","payload":{"resources":{"total":0,"plugins":[],"themes":[]},"grav":{"isUpdatable":false,"assets":{"grav-admin":{"name":"grav-admin-v1.6.21.zip","type":"application/octet-stream","size":10976381,"download":"https://getgrav.org/download/core/grav-admin/1.6.21"},"grav-update":{"name":"grav-update-v1.6.21.zip","type":"application/octet-stream","size":4097491,"download":"https://getgrav.org/download/core/grav-update/1.6.21"},"grav":{"name":"grav-v1.6.21.zip","type":"application/octet-stream","size":6265610,"download":"https://getgrav.org/download/core/grav/1.6.21"}},"version":"1.6.21","available":"1.6.21","date":"2020-02-12T00:17:52Z","isSymlink":false},"installed":29,"flushed":false}}`

If I remove the path or turn off Shortcode-Core the issue goes away.

I'm running the latest shortcode-core version (4.2.1) and latest Grav (Grav v1.6.21 - Admin v1.9.12)

Sorry won't let me format the error as code.