diff --git a/piker/data/feed.py b/piker/data/feed.py
index e4a998d5..e77052bf 100644
--- a/piker/data/feed.py
+++ b/piker/data/feed.py
@@ -397,7 +397,7 @@ async def start_backfill(
 
             diff = end_dt - start_dt
             frame_time_diff_s = diff.seconds
-            expected_frame_size_s = frame_size_s  # + step_size_s
+            expected_frame_size_s = frame_size_s + step_size_s
 
             if frame_time_diff_s > expected_frame_size_s:
 
@@ -522,8 +522,18 @@ async def start_backfill(
                     last_shm_prepend_dt = pendulum.from_timestamp(start)
                     earliest_frame_queue_dt = pendulum.from_timestamp(epoch)
 
-                    diff = epoch - start
-                    if abs(diff) > step_size_s:
+                    diff = start - epoch
+
+                    if diff < 0:
+                        log.warning(
+                            'Discarding out of order frame:\n'
+                            f'{earliest_frame_queue_dt}'
+                        )
+                        frames.pop(epoch)
+                        continue
+                        # await tractor.breakpoint()
+
+                    if diff > step_size_s:
 
                         if earliest_end_dt < earliest_frame_queue_dt:
                             # XXX: an expected gap was encountered (see
@@ -548,8 +558,32 @@ async def start_backfill(
                                     'then erlangs?\n'
                                     'There seems to be a gap between:\n'
                                     f'{earliest_frame_queue_dt} <- '
+                                    f'{last_shm_prepend_dt}\n'
+                                    'Conducting manual call for frame ending: '
                                     f'{last_shm_prepend_dt}'
                                 )
+                                (
+                                    to_push,
+                                    start_dt,
+                                    end_dt,
+                                ) = await get_ohlc_frame(
+                                        input_end_dt=last_shm_prepend_dt,
+                                        iter_dts_gen=idts,
+                                )
+                                last_epoch = to_push['time'][-1]
+                                diff = start - last_epoch
+
+                                if diff > step_size_s:
+                                    await tractor.breakpoint()
+                                    raise DataUnavailable(
+                                        'An awkward frame was found:\n'
+                                        f'{start_dt} -> {end_dt}:\n{to_push}'
+                                    )
+
+                                else:
+                                    frames[last_epoch] = (
+                                        to_push, start_dt, end_dt)
+                                    break
 
                             expect_end = pendulum.from_timestamp(start)
                             expect_start = expect_end.subtract(