Add on shows a warning that a dependency is missing

After successfully installing an add on (Behavior pack + Resource pack). Both were successfully installed.

I see both packs in my world setup and if I add the behavior pack it automatically adds the resource pack. Everything seems to work locally, but if I upload this world to my Realm the behavior pack seems still to work but the resources are not shown.

I also discovered that there is a warning under settings -> storage for this pack (See screenshots). I also checked the manifest.json for all the packs and the UUIDs and Versions are all right.

 

I tested this with Windows 10 Bedrock edition and on my Android 10. Minecraft version is 1.16.40