I have a an old list from December 2019 which showed the holders, supply and transfers in last 24h from Etherscan like here . Howvever while I was revisiting the addresses on Etherscan, there were a few address like this which now don't show any holders, supply or transfers. Any idea why this might be so?
Usually smart contract's source code must be validated by Etherscan to let it understand all functions and read it correctly, but the source code for the contract you referred is not verified.
It is very likely that contract does not follow the standard for names and functions, so even if Etherscan can vaguely understand that it represents a ERC-721 token, it can't read all informations.
Also note that token transactions are probably grabbed by Etherscan using events, so if some token does not fire events correctly or does not fire them as standards, there can be issues.