Laptop screen goes black, then comes back normal

Hi there.

i bought a Dell Inspiron 3585 last week for my other half.

its all been setup with everything she needs.

now, slight problem..

Some websites she visits, 9/10 times the screen will go black for 2-3 seconds then come back, but the pictures will be with just a green background.

when you refresh the webpage, it’ll do the same again.

the website is called: lensstudio.snapchat.com

it also happens on canva.com on certain pages.

any reason or ideas to why this is doing this? And any possible way I can fix this without sending the laptop back?

many thanks.