diff --git a/companion/src/firmwares/telem_data.cpp b/companion/src/firmwares/telem_data.cpp
index 15515e2a104..d474d48bc3d 100644
--- a/companion/src/firmwares/telem_data.cpp
+++ b/companion/src/firmwares/telem_data.cpp
@@ -61,9 +61,11 @@ void FrSkyData::clear()
   varioCenterMin = 0;    // if increment in 0.2m/s = 3.0m/s max
   varioCenterMax = 0;
   varioMax = 0;
+  varioCenterSilent = false;
   mAhPersistent = 0;
   storedMah = 0;
   fasOffset = 0;
+  ignoreSensorIds = false;
   for (int i=0; i<4; i++)
     screens[i].clear();
   varioSource = 0;
diff --git a/companion/src/tests/frsky_clear_test.cpp b/companion/src/tests/frsky_clear_test.cpp
new file mode 100644
index 00000000000..fb3b1827ab9
--- /dev/null
+++ b/companion/src/tests/frsky_clear_test.cpp
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "gtests.h"
+
+#include <cstring>
+
+#include "firmwares/telem_data.h"
+
+// FrSkyData::clear() is a hand-written field-by-field reset (not a memset),
+// so any field it forgets is left uninitialised. varioCenterSilent and
+// ignoreSensorIds were both omitted yet are serialised to YAML, which made a
+// freshly-cleared model emit non-deterministic values (e.g. centerSilent
+// emitted as a stray byte, then masked to 0/1 on reload -> non-idempotent
+// round-trip).
+//
+// Poison the storage first so the test fails deterministically if clear()
+// ever stops initialising one of these fields.
+TEST(FrSkyDataClear, InitialisesAllSerialisedFields)
+{
+  FrSkyData fs;
+  memset(reinterpret_cast<void*>(&fs), 0x2D, sizeof(fs));  // 0x2D == 45
+  fs.clear();
+
+  EXPECT_FALSE(fs.varioCenterSilent)
+      << "varioCenterSilent left uninitialised by FrSkyData::clear()";
+  EXPECT_FALSE(fs.ignoreSensorIds)
+      << "ignoreSensorIds left uninitialised by FrSkyData::clear()";
+}