diff --git a/hledger-lib/Hledger/Utils/Debug.hs b/hledger-lib/Hledger/Utils/Debug.hs
index 3e19254fa..ad8033685 100644
--- a/hledger-lib/Hledger/Utils/Debug.hs
+++ b/hledger-lib/Hledger/Utils/Debug.hs
@@ -303,8 +303,8 @@ plog = plogAt 0
 -- | Log a label and a pretty-printed showable value to ./debug.log,
 -- if the global debug level is at or above the specified level.
 -- At level 0, always logs. Otherwise, uses unsafePerformIO.
--- Tends to fail if called more than once, at least when built with -threaded
--- (Eg "Exception: debug.log: openFile: resource busy (file is locked)").
+-- Tends to fail if called more than once too quickly, at least when built with -threaded
+-- ("Exception: debug.log: openFile: resource busy (file is locked)").
 plogAt :: Show a => Int -> String -> a -> a
 plogAt lvl
     | lvl > 0 && debugLevel < lvl = flip const