diff --git a/pkg/core/native/native_test/cryptolib_verification_test.go b/pkg/core/native/native_test/cryptolib_verification_test.go
index 181a035bf..9b6dbaa22 100644
--- a/pkg/core/native/native_test/cryptolib_verification_test.go
+++ b/pkg/core/native/native_test/cryptolib_verification_test.go
@@ -635,7 +635,7 @@ func TestCryptoLib_KoblitzMultisigVerificationScript(t *testing.T) {
 
 		// Add some more network fee to pay for the witness verification. This value may be calculated precisely,
 		// but let's keep some inaccurate value for the test.
-		tx.NetworkFee += 900_0000
+		tx.NetworkFee = 8995470
 
 		// This transaction (along with the network magic) should be signed by the user's Koblitz private key.
 		msg := constructMsg(t, uint32(e.Chain.GetConfig().Magic), tx)
diff --git a/pkg/services/rpcsrv/server_test.go b/pkg/services/rpcsrv/server_test.go
index cd96f8dd1..439b27dd4 100644
--- a/pkg/services/rpcsrv/server_test.go
+++ b/pkg/services/rpcsrv/server_test.go
@@ -3152,10 +3152,13 @@ func testRPCProtocol(t *testing.T, doRPCCall func(string, string, *testing.T) []
 			body := doRPCCall(`{"jsonrpc": "2.0", "id": 1, "method": "calculatenetworkfee", "params": ["bm90IGEgdHJhbnNhY3Rpb24K"]}"`, httpSrv.URL, t)
 			_ = checkErrGetResult(t, body, true, neorpc.InvalidParamsCode, "Invalid params")
 		})
-		calcReq := func(t *testing.T, tx *transaction.Transaction) []byte {
-			rpc := fmt.Sprintf(`{"jsonrpc": "2.0", "id": 1, "method": "calculatenetworkfee", "params": ["%s"]}"`, base64.StdEncoding.EncodeToString(tx.Bytes()))
+		calcReqExactly := func(t *testing.T, tx string) []byte {
+			rpc := fmt.Sprintf(`{"jsonrpc": "2.0", "id": 1, "method": "calculatenetworkfee", "params": ["%s"]}"`, tx)
 			return doRPCCall(rpc, httpSrv.URL, t)
 		}
+		calcReq := func(t *testing.T, tx *transaction.Transaction) []byte {
+			return calcReqExactly(t, base64.StdEncoding.EncodeToString(tx.Bytes()))
+		}
 		t.Run("non-contract with zero verification", func(t *testing.T) {
 			tx := &transaction.Transaction{
 				Script:  []byte{byte(opcode.RET)},
@@ -3235,6 +3238,13 @@ func testRPCProtocol(t *testing.T, doRPCCall func(string, string, *testing.T) []
 			}
 			checkCalc(t, tx, 2315100) // Perfectly matches FeeIsMultiSigContract() C# test.
 		})
+		t.Run("Koblitz custom multisignature witness", func(t *testing.T) {
+			tx := "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"
+			resp := checkErrGetResult(t, calcReqExactly(t, tx), false, 0)
+			res := new(result.NetworkFee)
+			require.NoError(t, json.Unmarshal(resp, res))
+			require.Equal(t, int64(8995470), res.Value)
+		})
 		checkContract := func(t *testing.T, verAcc util.Uint160, invoc []byte, fee int64) {
 			txScript, err := smartcontract.CreateCallWithAssertScript(chain.UtilityTokenHash(), "transfer",
 				verAcc, verAcc, 1, nil)