This issue is due to some gaps in the NIP-47 spec that make it unclear how implementers should communicate sender/receiver information.
We have an open issue on the NIPs repo about this, with useful context and information: https://github.com/nostr-protocol/nips/issues/1843
Currently Damus is using the description field (following NIP-57 conventions) and/or the metadata field (following AlbyHub’s conventions) to communicate sender/receiver information.
