When I'm in single player or on a Mojang server, this bug (that shaders from spectating a mob persist after death) works. But, when I join a Spigot (or even Bukkit or Paper) server, it's fixed for me. Does anyone know why? I'm really curious

Works on Mojang: https://i.sstatic.net/3yc9V.jpg

Doesn't on Bukkit/Spigot/Paper: https://i.sstatic.net/zJcTh.jpg

Also, can make it so the bug works again?

I also asked this question on Spigot here: https://www.spigotmc.org/threads/why-is-the-spectator-bug-fixed-and-can-i-make-it-work-again.564535/