diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -892,11 +892,7 @@
             {"nodeid", RPCArg::Type::NUM, RPCArg::Optional::NO,
              "The node ID (see getpeerinfo for node IDs)"},
         },
-        RPCResult{RPCResult::Type::OBJ,
-                  "",
-                  "",
-                  {{RPCResult::Type::STR, "warnings", /*optional=*/true,
-                    "any warnings"}}},
+        RPCResult{RPCResult::Type::OBJ_EMPTY, "", /*optional=*/false, "", {}},
         RPCExamples{HelpExampleCli("getblockfrompeer",
                                    "\"00000000c937983704a73af28acdec37b049d214a"
                                    "dbda81d7e2a3dd146f6ed09\" 0") +
@@ -927,15 +923,15 @@
                 throw JSONRPCError(RPC_MISC_ERROR, "Block header missing");
             }
 
-            UniValue result = UniValue::VOBJ;
-
             if (index->nStatus.hasData()) {
-                result.pushKV("warnings", "Block already downloaded");
-            } else if (!peerman.FetchBlock(config, nodeid, *index)) {
+                throw JSONRPCError(RPC_MISC_ERROR, "Block already downloaded");
+            }
+
+            if (!peerman.FetchBlock(config, nodeid, *index)) {
                 throw JSONRPCError(RPC_MISC_ERROR,
                                    "Failed to fetch block from peer");
             }
-            return result;
+            return UniValue::VOBJ;
         },
     };
 }
diff --git a/src/rpc/util.h b/src/rpc/util.h
--- a/src/rpc/util.h
+++ b/src/rpc/util.h
@@ -253,6 +253,7 @@
         STR_AMOUNT, //!< Special string to represent a floating point amount
         STR_HEX,    //!< Special string with only hex chars
         OBJ_DYN,    //!< Special dictionary with keys that are not literals
+        OBJ_EMPTY,  //!< Special type to allow empty OBJ
         ARR_FIXED,  //!< Special array that has a fixed number of entries
         NUM_TIME,   //!< Special numeric to denote unix epoch time
         ELISION,    //!< Special type to denote elision (...)
diff --git a/src/rpc/util.cpp b/src/rpc/util.cpp
--- a/src/rpc/util.cpp
+++ b/src/rpc/util.cpp
@@ -785,6 +785,11 @@
             return;
         }
         case Type::OBJ_DYN:
+        case Type::OBJ_EMPTY: {
+            sections.PushSection(
+                {indent + maybe_key + "{}", Description("empty JSON object")});
+            return;
+        }
         case Type::OBJ: {
             sections.PushSection(
                 {indent + maybe_key + "{", Description("json object")});
@@ -836,6 +841,7 @@
             return UniValue::VARR == result.getType();
         }
         case Type::OBJ_DYN:
+        case Type::OBJ_EMPTY:
         case Type::OBJ: {
             return UniValue::VOBJ == result.getType();
         }
diff --git a/test/functional/rpc_getblockfrompeer.py b/test/functional/rpc_getblockfrompeer.py
--- a/test/functional/rpc_getblockfrompeer.py
+++ b/test/functional/rpc_getblockfrompeer.py
@@ -80,12 +80,14 @@
         self.log.info("Successful fetch")
         result = self.nodes[0].getblockfrompeer(short_tip, peer_0_peer_1_id)
         self.wait_until(lambda: self.check_for_block(short_tip), timeout=1)
-        assert "warnings" not in result
+        assert_equal(result, {})
 
         self.log.info("Don't fetch blocks we already have")
-        result = self.nodes[0].getblockfrompeer(short_tip, peer_0_peer_1_id)
-        assert "warnings" in result
-        assert_equal(result["warnings"], "Block already downloaded")
+        assert_raises_rpc_error(-1,
+                                "Block already downloaded",
+                                self.nodes[0].getblockfrompeer,
+                                short_tip,
+                                peer_0_peer_1_id)
 
 
 if __name__ == '__main__':