Tamed custom entites are named 'unknown' in death message when killed and in inventories.

Description:
When you have a tamed custom entity and it gets killed in any way, the death message show unknown instead of the given name of the custom entity.
The product where we noticed this issue heavily uses tamed custom entities and the only solution for the death messages would be turning off death messages which is not a good solution in our opinion.

Update: In further development we noticed that entities are called 'unknown' in inventories as well. Using the inventory component on tamed custom entities is a major feature of the product we noticed this in.

Impact: Seeing your tamed mobs named 'unknown' in death messages and inventories makes the product look broken and incomplete.

Verification build: Version 1.16.20.54 build 4417012, Win10

Repro Steps (Death messages):
1. Create custom entity with taming component.
2. Give the custom entity a name through the language files.
3. Get ingame and summon your entity.
4. Enable death messages
5. Tame your entity.
6. Let the entity die. (Blow it up with a creeper for instance)

Observed Results:
See chat and observe that 'unknown' died through whatever reason.

Expected Results:
See chat and observe the given 'name' was killed by whatever reason.

 

Update:
Repro Steps (Inventory):
1. Create custom entity with inventory component.
2. Give the custom entity a name through the language files.
3. Get ingame and summon your entity.
4. Tame your entity.
5. Enter entities inventory

Observed Results:
See entity named 'unknown' in the inventory GUI.

Expected Results:
See entities given name in the inventory GUI.

Screenshots attached: No

Notes:
Custom Entities named in language files do work, but it seems they do not work in death messages and inventories.
I increased the bug's priority to important, because we can't work around the inventory showing 'unknown', and we believe many other partners products are impacted by this bug.