diff --git a/CHANGELOG.md b/CHANGELOG.md
index 59d65adb..13101f6f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 # Changelog
 
 ## 3.7.8.dev
+* Fix: time-range filter on a VTODO having DTSTART/DUE and also CREATED/COMPLETED used the CREATED->COMPLETED duration instead of the DTSTART->DUE one, so completed tasks were missing from (or wrongly returned by) calendar-query REPORT results
 * Fix: sharing/proppatch: reject in case of write-access but 'p' is in permissions
 * Fix: sharing/by-map: catch collection path without trailing / (supporting "pimsync")
 * Add: [report] max_expand_occurrence option to separate from max_freebusy_occurrence
diff --git a/radicale/item/filter.py b/radicale/item/filter.py
index 74e571ca..789cafe3 100644
--- a/radicale/item/filter.py
+++ b/radicale/item/filter.py
@@ -442,7 +442,10 @@ def visit_time_ranges(vobject_item: vobject.base.Component, child_name: str,
                 completed = date_to_datetime(completed.value)
                 if created is not None:
                     created = date_to_datetime(created.value)
-                    original_duration = (completed - created).total_seconds()
+                    # NOTE: kept separate from "original_duration", otherwise a
+                    # VTODO with DTSTART+DUE and also CREATED+COMPLETED would
+                    # lose its DTSTART->DUE duration (see line 2 below)
+                    completed_duration = (completed - created).total_seconds()
             elif created is not None:
                 created = date_to_datetime(created.value)
 
@@ -500,7 +503,7 @@ def visit_time_ranges(vobject_item: vobject.base.Component, child_name: str,
                 elif completed is not None and created is not None:
                     # Line 5
                     completed = reference_date + timedelta(
-                        seconds=original_duration)
+                        seconds=completed_duration)
                     if (range_fn(reference_date - SECOND,
                                  reference_date + SECOND,
                                  is_recurrence) or
diff --git a/radicale/tests/static/todo10.ics b/radicale/tests/static/todo10.ics
new file mode 100644
index 00000000..5acbde84
--- /dev/null
+++ b/radicale/tests/static/todo10.ics
@@ -0,0 +1,13 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//Radicale//NONSGML Radicale Server//EN
+BEGIN:VTODO
+UID:todo10
+SUMMARY:todo10
+DTSTART:20130901T180000Z
+DUE:20130903T180000Z
+CREATED:20130901T170000Z
+COMPLETED:20130901T173000Z
+STATUS:COMPLETED
+END:VTODO
+END:VCALENDAR
diff --git a/radicale/tests/test_base.py b/radicale/tests/test_base.py
index 506d0871..7c2c2902 100644
--- a/radicale/tests/test_base.py
+++ b/radicale/tests/test_base.py
@@ -2083,6 +2083,27 @@ permissions: RrWw""")
 </C:comp-filter>"""], "todo", items=range(1, 9))
         assert "/calendar.ics/todo7.ics" in answer
 
+    def test_time_range_filter_todos_dtstart_due_completed(self) -> None:
+        """Report request with time-range filter on a completed todo which
+           also has DTSTART and DUE (rfc4791-9.9: DTSTART/DUE take
+           precedence over CREATED/COMPLETED)."""
+        # inside DTSTART..DUE, but outside CREATED..COMPLETED
+        answer = self._test_filter(["""\
+<C:comp-filter name="VCALENDAR">
+    <C:comp-filter name="VTODO">
+        <C:time-range start="20130902T000000Z" end="20130903T000000Z"/>
+    </C:comp-filter>
+</C:comp-filter>"""], "todo", items=(10,))
+        assert "/calendar.ics/todo10.ics" in answer
+        # entirely before DTSTART and CREATED
+        answer = self._test_filter(["""\
+<C:comp-filter name="VCALENDAR">
+    <C:comp-filter name="VTODO">
+        <C:time-range start="20130801T000000Z" end="20130901T000000Z"/>
+    </C:comp-filter>
+</C:comp-filter>"""], "todo", items=(10,))
+        assert "/calendar.ics/todo10.ics" not in answer
+
     def test_time_range_filter_events_valarm(self) -> None:
         """Report request with time-range filter on events having absolute VALARM."""
         answer = self._test_filter(["""\