diff --git a/common/pvahelper.h b/common/pvahelper.h
index 3209c30..e47fcaf 100644
--- a/common/pvahelper.h
+++ b/common/pvahelper.h
@@ -256,6 +256,7 @@ public:
 
             } else {
 
+                changed |= updated;
                 if(p_postone())
                     req = requester;
                 oflow = inoverflow = false;
@@ -280,6 +281,7 @@ public:
 
             } else {
 
+                changed |= updated;
                 if(p_postone())
                     req = requester;
                 oflow = inoverflow = false;
diff --git a/pdbApp/pdbgroup.cpp b/pdbApp/pdbgroup.cpp
index 238bacb..41fad32 100644
--- a/pdbApp/pdbgroup.cpp
+++ b/pdbApp/pdbgroup.cpp
@@ -322,6 +322,7 @@ void PDBGroupMonitor::onStart()
         }
         pv->initial_waits = ievts;
         pv->scratch.clear();
+        pv->scratch.set(0);
     } else if(pv->initial_waits==0) {
         // new subscriber and already had initial update
         post();
diff --git a/testApp/testmon.cpp b/testApp/testmon.cpp
index f61928e..315e9ba 100644
--- a/testApp/testmon.cpp
+++ b/testApp/testmon.cpp
@@ -86,6 +86,8 @@ struct TestMonitor {
         testOk1(mreq->eventCnt==1);
         pvd::MonitorElementPtr elem(mon->poll());
         testOk1(!!elem.get());
+        if(!!elem.get()) testEqual(toString(*elem->changedBitSet), "{0}");
+        else testFail("oops");
         testOk1(elem && elem->pvStructurePtr->getSubFieldT<pvd::PVInt>("x")->get()==1);
 
         if(elem) mon->release(elem);
diff --git a/testApp/testpdb.cpp b/testApp/testpdb.cpp
index 80bb503..176119d 100644
--- a/testApp/testpdb.cpp
+++ b/testApp/testpdb.cpp
@@ -305,6 +305,8 @@ void testSingleMonitor(const PDBProvider::shared_pointer& prov)
 
     e = mon.poll();
     testOk1(!!e);
+    if(!!e) testEqual(toString(*e.elem->changedBitSet), "{1, 3, 4}");
+    else testFail("oops");
     testFieldEqual<pvd::PVDouble>(e, "value", 11.0);
 
     e = mon.poll();
@@ -318,6 +320,8 @@ void testSingleMonitor(const PDBProvider::shared_pointer& prov)
 
     e = mon.poll();
     testOk1(!!e);
+    if(!!e) testEqual(toString(*e.elem->changedBitSet), "{11, 12, 14, 15, 17, 18}");
+    else testFail("oops");
     testFieldEqual<pvd::PVDouble>(e, "display.limitHigh", 50.0);
 
     e = mon.poll();
@@ -346,6 +350,8 @@ void testGroupMonitor(const PDBProvider::shared_pointer& prov)
     e = mon.poll();
     testOk1(!!e);
 
+    if(!!e) testEqual(toString(*e.elem->changedBitSet), "{0, 2, 4, 5, 12, 13, 15, 16, 18, 19, 22, 24, 25, 32, 33, 35, 36, 38, 39, 42, 44, 45, 52, 53, 55, 56, 58, 59, 62, 64, 65, 72, 73, 75, 76, 78, 79}");
+    else testFail("oops");
     testFieldEqual<pvd::PVDouble>(e, "fld1.value", 3.0);
     testFieldEqual<pvd::PVInt>(e,    "fld2.value", 30);
     testFieldEqual<pvd::PVDouble>(e, "fld3.value", 4.0);
@@ -354,6 +360,22 @@ void testGroupMonitor(const PDBProvider::shared_pointer& prov)
     testFieldEqual<pvd::PVDouble>(e, "fld1.display.limitLow", -200.0);
     testFieldEqual<pvd::PVDouble>(e, "fld2.display.limitHigh", 2147483647.0);
     testFieldEqual<pvd::PVDouble>(e, "fld2.display.limitLow", -2147483648.0);
+
+    e = mon.poll();
+    testOk1(!e);
+
+    testdbPutFieldOk("rec3", DBR_DOUBLE, 32.0);
+
+    testDiag("Wait for event");
+    testOk1(mon.monreq->waitForEvent());
+    testDiag("event");
+
+    e = mon.poll();
+    testOk1(!!e);
+    if(!!e) testEqual(toString(*e.elem->changedBitSet), "{2, 4, 5}");
+    else testFail("oops");
+
+    testFieldEqual<pvd::PVDouble>(e, "fld1.value", 32.0);
 }
 
 } // namespace
diff --git a/testApp/testpvif.cpp b/testApp/testpvif.cpp
index ac81ebf..d060eb5 100644
--- a/testApp/testpvif.cpp
+++ b/testApp/testpvif.cpp
@@ -75,6 +75,9 @@ void testScalar()
     pvif_li->put(mask, DBE_VALUE|DBE_ALARM|DBE_PROPERTY, NULL);
     dbScanUnlock((dbCommon*)prec_li);
 
+    testEqual(toString(mask), "{2, 4, 5, 12, 13, 15, 16, 18, 19}");
+    mask.clear();
+
     dbScanLock((dbCommon*)prec_ai);
     prec_ai->time.secPastEpoch = 0x12345678;
     prec_ai->time.nsec = 12345678;
@@ -82,12 +85,18 @@ void testScalar()
     pvif_ai_rval->put(mask, DBE_VALUE|DBE_ALARM|DBE_PROPERTY, NULL);
     dbScanUnlock((dbCommon*)prec_ai);
 
+    testEqual(toString(mask), "{22, 24, 25, 32, 33, 35, 36, 38, 39, 42, 44, 45, 52, 53, 55, 56, 58, 59}");
+    mask.clear();
+
     dbScanLock((dbCommon*)prec_mbbi);
     prec_mbbi->time.secPastEpoch = 0x12345678;
     prec_mbbi->time.nsec = 12345678;
     pvif_mbbi->put(mask, DBE_VALUE|DBE_ALARM|DBE_PROPERTY, NULL);
     dbScanUnlock((dbCommon*)prec_mbbi);
 
+    testEqual(toString(mask), "{63, 64, 66, 67}");
+    mask.clear();
+
     testFieldEqual<pvd::PVInt>(root, "li.value", 102042);
     testFieldEqual<pvd::PVInt>(root, "li.alarm.severity", 1);
     testFieldEqual<pvd::PVLong>(root, "li.timeStamp.secondsPastEpoch", 0x12345678);
@@ -130,6 +139,11 @@ void testScalar()
     root->getSubFieldT<pvd::PVDouble>("ai.value")->put(44.4);
     root->getSubFieldT<pvd::PVInt>("mbbi.value.index")->put(2);
 
+    mask.clear();
+    mask.set(root->getSubFieldT<pvd::PVInt>("li.value")->getFieldOffset());
+    mask.set(root->getSubFieldT<pvd::PVDouble>("ai.value")->getFieldOffset());
+    mask.set(root->getSubFieldT<pvd::PVInt>("mbbi.value.index")->getFieldOffset());
+
     dbScanLock((dbCommon*)prec_li);
     pvif_li->get(mask);
     testOk1(prec_li->val==102043);