If you've noticed that your Bitcoin receiving address changes every time you go to receive a payment in the Blockstream App, don’t worry, this is completely normal and actually a privacy feature.
Each time you tap to receive bitcoin in the Blockstream App, the app generates a new, unused address from your wallet. Even though the address changes, all of them are still connected to your same wallet, and you can access any funds sent to those addresses at any time.
This design helps protect your privacy. Because all Bitcoin transactions are recorded on a public ledger (called the blockchain), using the same address over and over can make it easy for someone to track your payments or estimate how much bitcoin you have. By using a new address for each payment, you make it much harder for others to link your transactions together.
Note: Even if someone sends bitcoin to an older address you used before, you’ll still receive the funds without any issues. All of your addresses are still part of your wallet, they just aren’t reused by default.
This is considered best practice in the Bitcoin world, and the Blockstream App handles it automatically for you, so you get better privacy without having to think about it.