Transaction scanning is non-standard
When we scan transactions we either use the additional public key at the outputs index or if there are no additional public keys we use the main public key for all outputs:

https://github.com/monero-rs/monero-rs/blob/main/src/blockdata/transaction.rs#L544-L568

This is different than Monero which tries both:

https://github.com/monero-project/monero/blob/master/src/cryptonote_basic/cryptonote_format_utils.cpp#L1047

