When my CoinPocket wallet APP was disconnected, someone transferred BTC bitcoin to me.

Yes. Bitcoin (BTC) will appear in your account the next time you open the wallet program after connecting to the Internet. Bitcoins are not actually received by the wallet software, they are added to a public ledger shared by all the devices on the network.

If someone transfers BTC to you when your wallet is not running, the wallet will download the block data and update any unrecorded transactions when you open your wallet later, and the BTC record of the transfer will appear in the wallet.