papafigos on Nostr: they know in the sense that they used a stealth address to put it there. but they ...

they know in the sense that they used a stealth address to put it there.

but they can't see when the funds have moved (only probabilistically and this is about to get much better with FCMP++), and they can't see if the funds are still there (addresses don't actually really exist in monero).

so, in no meaningful way can it be said that the sender knows, other than the self-evident piece or knowledge that is the monero address that was shared (can be used for offchain correlations), and the utxo that the sender knows, because they made the transaction.

this is the old Supertestnet "logic', and it's flawed. he's been destroyed in debate on this topic too many times to count, and eventually just stops replying when he realizes he is up against someone who actually understands ring signatures.

BUT you are right that it is a weakness in monero right now, it even enables some attack vectors under specific conditions, which shouldn't happen.

those few attack vectors and this ring signatures probabilitic imperfection will largely go away with the upcoming FCMP++ upgrade, read about it if you haven't yet.