I don't think the pool is not allowing the address to mine on it, he probably has a problem with his miner/internet and not the address he uses, how can a pool tell the difference between a legacy address which belongs BCH/BTC, it can't because there is no difference between the addresses.

136CrBTFqaLShQVTzhH2MRUauRrrzP7JbG is valid P2PKH/Pay To Pubkey Hash bitcoin address, even if that address was generated from a BCH wallet, it can still receive a BTC block reward provided he has the private key for it, someone please correct me if I am mistaken.