The developer network tools actually showed that the favicon wasn’t delayed in being requested just another request was still downloading something that didn’t show up on GTMetrix…. might be worth investigating to see if something similar is occurring.
This is a screenshot from the Network tab in the Browser Dev Tools. You can see your favicon – its being loaded almost immediately after the previous all the other requests are completed. So GTMetrix is not displaying the additional time to load those files – hence it looks like there is a pointless delay.