After content is posted, theme loading slows

Hello! This bug is with both version 5.x-1.3 and 5.x-1.2, and happens after creating the first node. The theme loads fine, however it loads header first and then content and is noticeably slower than with just a clean install. This is not a server related issue, because I have tested this with other themes (ie garland and other core themes) and it works as it should and loads everything at the same time.