Cubed currently has skDragon 0.15 which is broken on 1.15 and 1.16 playerserver. There are already 2 update to it which let it work on 1.15/1.16 and add some new particle on those version, so it would be great if this plugin get updated.
Download skDragon 0.17 here: https://www.spigotmc.org/resources/skript-addon-skdragon-free-emotes-particles-great-eula-perks.24173/download?version=357891