Is it possible the wallet is looking for a private key format that differs from the one provided on the coin? I’m not an expert in redeeming private keys but there have been numerous struggles with people trying to redeem improper formats etc.
Have you tried other wallets to import it with? Does it come up as invalid everywhere?
it is possible that he is not importing them correctly and thus getting a different "address' for example below using electrum,
If the address starts with a "3" you have to prepend “p2wpkh-p2sh:” before the private key.
If the addresses begin with "bc1" then you prepend “p2wpkh:” before the private key.
See this is exactly my point. Importing a private key isn’t as simple and universal as copy/pasting an address. I didn’t even know about what you just described.
However I think he’s saying that the address he’s looking at is via firstbits from the outside hologram. I don’t think the private key he’s using is returning anything at all.