Again we can observe this message on Bitcoin Core full nodes:

Related topics:

https://www.reddit.com/r/Bitcoin/comments/aq69kd/bitcoin_core_wallet_message_warning_unknown_block/
https://www.reddit.com/r/Bitcoin/comments/aq6fyq/i_saw_this_message_on_my_full_node_what_does_it/
https://github.com/bitcoin/bitcoin/pull/13972

and a quote:
"False positive warnings are toxic because it leads to node operators ignoring warning messages, thus defeating the purpose of a warning system."