Image Sliders not loading properly

Hi, I just looked at my website using Safari on a new Apple Mac, and I noticed that some of the image sliders don’t display properly when the page first loads – they are much too small. However, if I wait a while and then refresh the page, everything returns to normal. I’m not sure what’s happening – is it a loading issue perhaps? Or do I need to set a minimum width sliders? So far three pages have had problems but it doesn’t happen every time :

https://www.centrepiecedesign.com/products/
https://www.centrepiecedesign.com/bespoke-tables/
https://www.centrepiecedesign.com/coffee-table/

I haven’t had any issues with Internet Explorer, Chrome or Firefox.

Hoping someone can help. Thanks in advance, Mark.