A marker's data tag can be shared among multiple markers

The bug

A marker's data tag can be shared among multiple markers.

When an entity teleports to another dimension, the entity in the current dimension is removed and its copy is created in the destination dimension. If you teleport an entity to multiple dimensions, you can create the corresponding number of copies of it. When the teleport target is a marker entity, data tag sharing occurs among the copies because a marker's data tag is not copied on serialization.

How to reproduce

1. Enable the datapack in Attachments.
2. Execute

   /function mc-223382:init

3. Execute

   /debug function mc-223382:run

   → Markers' data tags are modified by modifications to other markers. The markers e2 and e3 are now in a shared state, and any modifications to one's data tag will be reflected in the other.