Much like Wordfence, you'll get a lot of "false" reports with Sucuri if you combine it with Shield.
This is an artifact of using 2+ systems that hook into the same places to monitor activity.
If you want to understand how Shield is handling requests to your site, use the Audit Trail within Shield itself. But do not use both Shield and Sucuri and then rely on the reports you receive from Sucuri about things that Shield is supposedly blocking... these are not reliable reports.
Shield does not send out reports about requests that are blocked because this type of security mitigation does not scale. Imagine you had 100+ websites all doing the same thing...
Shield is built to scale and to leave you alone unless you really need or want to know something. Otherwise, best to leave it to do its job and monitor it using the Audit Trail if you need to.
-If you really still think there is something strange going on that needs investigating, please contact us.