Dear Beky,
'Blinking Behaviour' or 'Page Blank' will happen to all the customers who have their Header and Footer components embedded within their body. In Target, you would have enabled 'Body Hiding' inside target for the purpose to avoid flickering. So, Target will hide your entire body for a fraction of seconds before the response is received from the target leading to 'Blinking Behaviour' or 'Page Blank'. We have faced the same issue before years and went on with deep learning and exercises to avoid this, but the result is nill. Then we placed the Header and Footer Components out of Body. Then, on the page load, Header and Footer will load without hiding giving the experience to the customers that the page started loading already avoiding the 'Blinking Behaviour' or 'Page Blank'. Or you can ignore the entire 'Body Hiding' instead use the container you want to hide, this is also possible in Target.
body {opacity: 0 !important}
Change it to your container or ID.
#MyContainerID {opacity: 0 !important}
Thank You, Arun.