Explain the Concept of ‘Orphaning’ a Block in a Proof-of-Work Blockchain

Orphaning occurs when two valid blocks are mined almost simultaneously, creating a temporary fork. The network nodes accept the first one they see.

When a longer chain is eventually established, the blocks not included in that longest chain are 'orphaned' or discarded. The transactions in the orphaned block are returned to the mempool, and the miner who found the orphaned block loses the block reward.

This is a normal part of PoW operation.