diff --git a/piker/fsp/_engine.py b/piker/fsp/_engine.py
index f9a4f797..a78308a4 100644
--- a/piker/fsp/_engine.py
+++ b/piker/fsp/_engine.py
@@ -21,7 +21,9 @@ core task logic for processing chains
 from dataclasses import dataclass
 from functools import partial
 from typing import (
-    AsyncIterator, Callable, Optional,
+    AsyncIterator,
+    Callable,
+    Optional,
     Union,
 )
 
@@ -386,7 +388,7 @@ async def cascade(
                 ) -> tuple[TaskTracker, int]:
                     # TODO: adopt an incremental update engine/approach
                     # where possible here eventually!
-                    log.debug(f're-syncing fsp {func_name} to source')
+                    log.info(f're-syncing fsp {func_name} to source')
                     tracker.cs.cancel()
                     await tracker.complete.wait()
                     tracker, index = await n.start(fsp_target)
@@ -429,6 +431,7 @@ async def cascade(
                     tracker: TaskTracker,
                     src: ShmArray,
                     dst: ShmArray,
+
                 ) -> tuple[TaskTracker, int]:
 
                     synced, step_diff, _ = is_synced(src, dst)
@@ -444,7 +447,8 @@ async def cascade(
                 # signal
                 times = src.array['time']
                 if len(times) > 1:
-                    delay_s = float(times[-1] - times[times != times[-1]][-1])
+                    last_ts = times[-1]
+                    delay_s = float(last_ts - times[times != last_ts][-1])
                 else:
                     # our default "HFT" sample rate.
                     delay_s = _default_delay_s