Is RPC error 32603 specific to certain transactions or operations in MetaMask?

Yes, RPC error 32603 can occur during various transactions, including sending tokens, interacting with smart contracts (like DeFi platforms), and fetching data from the blockchain. It's not limited to a single action, but rather a general indicator of a problem interacting with the Ethereum network. It's more likely to happen when interacting with complex or computationally intensive smart contracts.