Your frying temperature is likely too high. The outside is cooking too quickly, leaving the inside raw.
When frying bondas, maintaining the correct oil temperature is crucial for even cooking. If the oil is too hot, the outside will brown and crisp up rapidly, giving the illusion that the bonda is cooked through. However, the heat hasn't had enough time to penetrate to the center, leaving the batter inside raw and uncooked.
To fix this, lower your oil temperature. A good starting point is around 160°C to 175°C (320°F to 347°F). Use a thermometer to monitor the oil temperature accurately. Fry the bondas in smaller batches to prevent the oil temperature from dropping too much when you add the cold batter. Allow the bondas to cook slowly, ensuring the heat reaches the center. You can also try flipping them more frequently to promote even cooking. If the bondas are browning too quickly even at a lower temperature, reduce the heat further.
Before frying a whole batch, test one bonda to check the oil temperature and cooking time. Cut it open after frying to ensure the inside is cooked through. Adjust the temperature accordingly before proceeding with the rest of the batch.