A texture pack/McAddon keeps showing up on my Realm WITHOUT me adding or even purchasing what shows up. The McAddon is “Sonic the Hedgehog”.

Good afternoon, I'm running into a problem with a Realm that I just bought a few days ago. In the beginning there was no major problem until more people connected to the server. The Realm started showing them a Sonic McAddon despite never having purchased it, the issue persisted for all guests until it occurred on my account.
As can be seen in the images I never added this package, all that can be seen were downloaded from an external application as a method of making the Realm more varied. What can I do this time to remove this bug? Many users of my Realm have already complained about how the texture pack tends to bother the eyes because of the colors, to the point that many have abandoned it.