Epoch index value is Null at start of blockchain instead of int 0

Using gdev docker image with runtime 900 or gtest docker image with runtime 1000, Epoch index value is Null at start of blockchain instead of int 0.

To be accurate a request of the storage value of : Babe.EpochIndex returns Null (None in python) instead of int 0.

API response:

{'id': 1, 'jsonrpc': '2.0', 'result': None}

While logs display the correct epoch index number #0 :

duniter-v2s-gdev-800  | 2025-07-18 13:25:06 👶 New epoch 0 launching at block 0xba98…e50e (block slot 292140851 >= start slot 292140851).    
duniter-v2s-gdev-800  | 2025-07-18 13:25:06 👶 Next epoch starts at slot 292140881    
duniter-v2s-gdev-800  | 2025-07-18 13:25:06 🏆 Imported #1 (0x74d0…e431 → 0xba98…e50e)

API should returns 0 integer.