try this

pioreactor/background_jobs/base.py

@@ -26,6 +26,7 @@
 from pioreactor.utils import append_signal_handlers
 from pioreactor.utils import is_pio_job_running
 from pioreactor.utils import JobManager
+from pioreactor.utils.timing import catchtime
 from pioreactor.utils.timing import RepeatedTimer
 from pioreactor.whoami import is_active
 from pioreactor.whoami import is_testing_env
@@ -1125,8 +1126,9 @@ def sneak_in(ads_interval, post_delay, pre_delay) -> None:
             if self.state != self.READY:
                 return
 
-            self._action_to_do_after_od_reading()
-            sleep(ads_interval - self.OD_READING_DURATION - (post_delay + pre_delay))
+            with catchtime() as timer:
+                self._action_to_do_after_od_reading()
+            sleep(ads_interval - self.OD_READING_DURATION - (post_delay + pre_delay) - timer())
             self._action_to_do_before_od_reading()
 
         # this could fail in the following way:

pioreactor/background_jobs/stirring.py

@@ -283,10 +283,8 @@ def __init__(
 
     def action_to_do_before_od_reading(self):
         self.set_duty_cycle(0)
-        self.logger.debug("stop stirring")
 
     def action_to_do_after_od_reading(self):
-        self.logger.debug("starting stirring")
         self.start_stirring()
         sleep(1)
         self.poll_and_update_dc(2)