diff --git a/src/stratum.cpp b/src/stratum.cpp
index 16736e6e2..7877dd171 100644
--- a/src/stratum.cpp
+++ b/src/stratum.cpp
@@ -656,9 +656,18 @@ void CustomizeWork(const StratumClient& client, const StratumWork& current_work,
             LogPrint("stratum", "%s\n", msg);
             throw std::runtime_error(msg);
         }
-        if (cb.vout[0].scriptPubKey == (CScript() << OP_FALSE)) {
-            cb.vout[0].scriptPubKey = GetScriptForDestination(addr.Get());
+        // Unconditional. This used to be guarded on the coinbase still carrying the OP_FALSE
+        // placeholder, which made it a no-op for every client after the first once a customized
+        // coinbase had been written back into the shared template -- so those miners silently
+        // mined the first miner's payout address. The template is now left pristine (see
+        // GetWorkUnit), and stamping unconditionally means a coinbase that somehow arrives
+        // already customized can never be inherited by a different miner.
+        if (!addr.IsValid()) {
+            const std::string msg = strprintf("%s: no valid payout address for this client; unable to customize work", __func__);
+            LogPrint("stratum", "%s\n", msg);
+            throw std::runtime_error(msg);
         }
+        cb.vout[0].scriptPubKey = GetScriptForDestination(addr.Get());
     }
 
     // cb_branch = current_work.m_cb_branch;
@@ -864,20 +873,24 @@ std::string GetWorkUnit(StratumClient& client)
         static const std::vector<unsigned char> dummy(32-extranonce1.size(), 0x00); // extranonce2
         CustomizeWork(client, current_work, client.m_addr, extranonce1, dummy, cb, bf, cb_branch);
 
-        // without 2 lines below equihash solutinon on SubmitWork will be incorrect, bcz we should
-        // change vtx[0] in current work and re-calc hashMerkleRoot
-        // TODO: refactor all of these ... may be change this in current_work directly is bad idea,
-        // and we should do all checks and hashMerkleRoot at SubmitBlock(...)
-
-        current_work.GetBlock().vtx[0] = cb;
-        current_work.GetBlock().hashMerkleRoot = current_work.GetBlock().BuildMerkleTree();
-
     }
 
     CBlockHeader blkhdr;
     // Setup native proof-of-work
 
-    blkhdr = current_work.GetBlock().GetBlockHeader(); // copy entire blockheader created with CreateNewBlock to blkhdr
+    // The shared template MUST keep its pristine OP_FALSE coinbase. This previously did
+    //     current_work.GetBlock().vtx[0] = cb;
+    //     current_work.GetBlock().hashMerkleRoot = current_work.GetBlock().BuildMerkleTree();
+    // which published one client's coinbase to every other client on the same job: the merkle
+    // root they were told to mine, and the block they eventually submitted, both committed to
+    // the first client's payout address. Derive this client's header from a local copy instead,
+    // which is what the TODO that used to sit here was asking for.
+    {
+        CBlock tmp(current_work.GetBlock());
+        tmp.vtx[0] = cb;
+        blkhdr = tmp.GetBlockHeader();
+        blkhdr.hashMerkleRoot = tmp.BuildMerkleTree();
+    }
     // CDataStream ds(SER_GETHASH, SERIALIZE_TRANSACTION_NO_WITNESS);
     CDataStream ds(SER_GETHASH, PROTOCOL_VERSION);
     ds << cb;
@@ -1012,7 +1025,14 @@ bool SubmitBlock(StratumClient& client, const uint256& job_id, const StratumWork
                          : std::vector<unsigned char>(sol.begin() + 3, sol.end());
 
         blkhdr.hashFinalSaplingRoot = current_work.GetBlock().hashFinalSaplingRoot;
-        blkhdr.hashMerkleRoot = current_work.GetBlock().hashMerkleRoot;
+        // Recompute from the coinbase CustomizeWork() just derived for THIS client. Reading the
+        // shared template's root would be wrong now that the template is left pristine, and was
+        // wrong before too -- it carried whichever client happened to request work first.
+        {
+            CBlock tmp(current_work.GetBlock());
+            tmp.vtx[0] = cb;
+            blkhdr.hashMerkleRoot = tmp.BuildMerkleTree();
+        }
         blkhdr.nNonce = (uint256) nonce;
 
         // block is constructed, now it's time to VerifyEH