Was playing on a realm on Ps5 with a friend also on Ps5and was using a Elytra and there one changed colour even though they weren't wearing a Cape it matched the Cape I was wearing. Did testing on other worlds that one of which I created and a second my friend did and it still happened. One of us could see the colours the other couldn't and doesn't matter if wearing a one of you is wearing a Cape they either go to grey or colour

 First Noticed in survival but also does it in creative 

Here is a link of a recording of what happens shared via one drive

https://1drv.ms/v/s!Auuxq7c2uncogaZF-0rBz-VjJMZbag