Which NFT is considered original if the creator mints it on two different blockchains with the same source link?
This depends on the intentions of the creator but also on what the market thinks where the
value of the NFT lies. Usually, the original one is the first one from a temporal point of view.
This is especially relevant in the context of IP infringements where a different creator tries to
copycat the original creator.
However, in the context of NFTs and blockchains, the same creator and/or the market might
decide on a different point of view. For example, testing the NFTs’ smart contracts on one of
the Etherium testnets will usually not be considered the original NFT. Instead, minting it on
the Etherium Mainnet will be the original NFT for the creator but also for the market. In
addition, the market might also decide that a different/newer fork of the blockchain is the
“original”, for example in the “Merge” where the Etherium blockchain is converted from a
Proof-of-Work-based blockchain to a Proof-of-Stake one and both continue to exist.
At first, both will be considered original, since they coexist in different networks,
unless there is a manifestation to that effect.