Using runtime_identifier in a custom entity and killing it will display in chat the runtime_identifier instead of the entity identifier

Steps to reproduce:
1.- Summon a custom entity that has a runtime identifier (identifier: "custom:entity_name", runtime_identifier: "minecraft:cow"
2.- Make sure that the entity does not have any name in the lang files
3.- Kill the entity with commands (/kill @e[type=custom:entity_name,c=1])
4.- You will see that it appears "Killed Cow", instead of "Killed custom:entity_name"

Expaected Behaviour:
-Should appear "Killed custom:entity_name"