Why do I see a Bitcoin address prefix starting with 4? I have an old Bitcoin (Counterparty) wallet that I am importing past transactions. I found a Tx that has a missing output address on one API, but it shows on another. I cannot find any documentation on what the Bitcoin address prefixed with '4' means. Is this valid or just a place holder?
Tx Hash: 5288973c6e2a323a2fbc95b84fbfd18b4ed2f75895c8295db03c653ea58c70d6
Blockcypher is showing the '4' (4PTehVhW6qTNhn88DK3JPBMkXfB2wR4juB)
https://api.blockcypher.com/v1/btc/main/txs/5288973c6e2a323a2fbc95b84fbfd18b4ed2f75895c8295db03c653ea58c70d6
Original API call is through Blockchain.Info
https://www.blockchain.com/btc/tx/5288973c6e2a323a2fbc95b84fbfd18b4ed2f75895c8295db03c653ea58c70d6
Blockchain just says &quot;Unable to decode output address&quot;.
This is a counterparty transaction so I am thinking it may have something to do with that. Thoughts?
I see it as multisig script on OXT

Blockchair shows it as multisig address: m-99d8dc4aa2b7f5b105fe442f651d73e6

blockstream.info shows UNKNOWN