Guest optimisation causing FOUC

My hompage is showing FOUC momentarily before loading, it looks pretty dramatic and i’v narrowed it down to guest optimisation, It appears to be only affecting my home page. When i turn off guest optimisation it displays correctly, but when its on it looks completely out of wack on the first load, this is seen on pagespeed insights as well as loading it on my browser.

My speed scores are great but i’d prefer to not have such dramatic FOUC if there is away