If you're getting errors when doing address lookups, it's probably because of your Electrum server backend.
Mempool uses an Electrum server to do address lookups. There are several implementations of the Electrum server protocol, and Mempool can use any of them, but the implementation you use affects performance:
If a transaction reveals a multisig script (threshold + public keys) and enough of the keys to meet the threshold were generated on a Coldcard with the pre-fix firmware (or otherwise weak entropy) and lack sufficient extra entropy/passphrase, the funds may be at elevated risk of theft while unconfirmed.
+If an address has been used and reveals a multisig script (threshold + public keys) and enough of the keys to meet the threshold were generated on a Coldcard with the pre-fix firmware (or otherwise weak entropy) and lack sufficient extra entropy/passphrase, the funds in the address are vulnerable.
+ +