There is death in Satyaloka. Let's examine the verse in context:
The duration of life in Satyaloka is calculated to be 15,480,000,000,000 years. In ... Satyaloka, there is neither bereavement, nor old age nor death.
So in Satyaloka, the world of Brahma, life is not eternal. It is just that while Satyaloka itself exists, there is no death there. But eventually Satyaloka itself is destroyed, and that's when its inhabitants finally die.
Let me explain the figure "15,480,000,000,000 years", by the way. As I discuss in this answer, the four Yugas make up one Mahayuga, and 1000 Mahayugas make up a Kalpa. Now a Kalpa is one day for Brahma, who goes to sleep at the end of the Kalpa after which a Pralaya or period of destruction ensues. And then Brahma wakes up and creates the world anew. Now if a Kalpa is one day for Brahma, just imagine how long a hundred years for Brahma is! That is called a Mahakalpa. At the end of a Mahakalpa, Brahma dies, and then there is a period of even greater destruction called a Mahapralaya. And then a new Brahma is born from Vishnu and the process starts all over again.
Now when Brahma dies, so do the inhabitants of Satyaloka who were worshipping him, and Brahma and those inhabitants all attain Moksha together, as described in a later chapter of the Srimad Bhagavatam:
Worshipers of the Hiraṇyagarbha expansion of the Personality of Godhead remain within this material world until the end of two parārdhas, when Lord Brahmā also dies. After experiencing the inhabitable time of the three modes of material nature, known as two parārdhas, Lord Brahmā closes the material universe, which is covered by layers of earth, water, air, fire, ether, mind, ego, etc., and goes back to Godhead. The yogīs who become detached from the material world by practice of breathing exercises and control of the mind reach the planet of Brahmā, which is far, far away. After giving up their bodies, they enter into the body of Lord Brahmā, and therefore when Brahmā is liberated and goes to the Supreme Personality of Godhead, who is the Supreme Brahman, such yogīs can also enter into the kingdom of God.
So that's the meaning of the duration of life given in that verse.