On bedrock realms, addons are applied without the order in mind.

I’ve always noticed addons on realms always seem to break, but with testing I only recently found out why. When using the music+ pack with the custom music pack it comes with, the addon didn’t register that I had applied the other, making it useless. This would also explain why multiple addons do not work on realms, as all of the items are given the same id.