An unsafe way to check if a property is defined is breaking the code, in production environments usually this issues are ignored to keep the site running but in development they typically throw an error and break the site.

The issue is happening in this line https://github.com/moodle/moodle/blob/MOODLE_405_STABLE/mod/lti/openid-registration.php#L55 and is very straight forward to fix, it only needs to wrap the property inside an "isset()", example:

if (isset($type->id)) {

How to reproduce the issue

Go to Site administration > Plugin > Activity modules > External tool > Manage tools

Add a valid URL and click "Add LTI Advantage", an error should be displayed in an iframe.

Step by step docs for connecting Moodle to Modle through LTI https://docs.moodle.org/500/en/LTI_Moodle_to_Moodle