The janusgraph docs and gitrepo talk about ghost vertices or phantom vertices:

https://docs.janusgraph.org/advanced-topics/eventual-consistency/#ghost-vertices
https://docs.janusgraph.org/basics/transactions/#transaction-configuration
https://github.com/JanusGraph/janusgraph/issues/2176

What happens if you try to delete the vertex with my_id = 2?

If this works, I am afraid there is not a more helpful answer than:
https://lists.lfaidata.foundation/g/janusgraph-users/topic/79936778#3898

If deleting the vertex does not work, you might want to mention this discussion in issue 2176, explaining why your issue is different from a ghost vertex.

Best wishes,    Marc