diff --git a/src/journal/src/Journal/Internal.hs b/src/journal/src/Journal/Internal.hs
index 1ff2c08e..20038bf7 100644
--- a/src/journal/src/Journal/Internal.hs
+++ b/src/journal/src/Journal/Internal.hs
@@ -62,6 +62,7 @@ tryClaim jour len = do
   putStrLn ("tryClaim, termCount: " ++ show (unTermCount termCount))
   putStrLn ("tryClaim, activePartitionIndex: " ++ show (unPartitionIndex activePartitionIndex))
   putStrLn ("tryClaim, termOffset: " ++ show (unTermOffset termOffset))
+  putStrLn ("tryClaim, termBeginPosition: " ++ show termBeginPosition)
   limit <- calculatePositionLimit jour
   let termAppender = jTermBuffers jour Vector.! unPartitionIndex activePartitionIndex
       position     = termBeginPosition + fromIntegral termOffset
diff --git a/src/journal/test/JournalTest.hs b/src/journal/test/JournalTest.hs
index 25a34c02..1ce05a0c 100644
--- a/src/journal/test/JournalTest.hs
+++ b/src/journal/test/JournalTest.hs
@@ -3,6 +3,7 @@
 
 module JournalTest where
 
+import Debug.Trace (trace)
 import Control.Arrow ((&&&))
 import Control.Exception (IOException, catch, displayException)
 import Control.Monad (unless, when)
@@ -44,36 +45,72 @@ startJournalFake = FakeJournal Vector.empty 0
 
 appendBSFake :: ByteString -> FakeJournal -> (FakeJournal, Either AppendError ())
 appendBSFake bs fj@(FakeJournal bss ix)
-  | unreadBytes < limit = (FakeJournal (Vector.snoc bss bs) ix, Right ())
+  | position < limit =
+    trace (unlines [ "TRACE"
+                   , "ix: " ++ show ix
+                   , "readBytes: " ++ show readBytes
+                   , "unreadBytes: " ++  show unreadBytes
+                   , "readPadBytes: " ++  show readPadBytes
+                   , "unreadPadBytes: " ++ show unreadPadBytes
+                   , "position: " ++ show position
+                   , "limit: " ++ show limit
+                   ])
+    (FakeJournal (Vector.snoc bss bs) ix, Right ())
   | otherwise           = (fj, Left BackPressure)
   where
     termLen :: Int
     termLen = oTermBufferLength testOptions
 
+    position = readBytes + unreadBytes
+
     limit :: Int
-    limit = termLen `div` 2
+    limit = readBytes + termLen `div` 2
+
+    readBytes :: Int
+    readBytes = (+ readPadBytes)
+              . Vector.sum
+              . Vector.map (\bs -> hEADER_LENGTH + BS.length bs)
+              $ Vector.slice 0 (max 0 (ix - 1)) bss
 
     unreadBytes :: Int
     unreadBytes = sum [ hEADER_LENGTH + BS.length bs
                       | bs <- map (bss Vector.!) [ix..Vector.length bss - 1]
                       ]
-                + padBytes
+                + unreadPadBytes
+
+    -- XXX: figure out why this doesn't work:
+    -- unreadBytes :: Int
+    -- unreadBytes = (+ unreadPadBytes)
+    --             . Vector.sum
+    --             . Vector.map (\bs -> hEADER_LENGTH + BS.length bs)
+    --             $ Vector.slice ix (max 0 (Vector.length bss - 1)) bss
+
 
-    padBytes :: Int
-    padBytes =
+    readPadBytes, unreadPadBytes :: Int
+    (readPadBytes, unreadPadBytes) =
       let
-        (lbss, rbss) = Vector.splitAt ix bss
-        (lacc, lpad) = padding 0 0 (Vector.toList (Vector.map BS.length lbss))
-        (racc, rpad) = padding lacc 0 (Vector.toList (Vector.map BS.length rbss))
+        (lbss, rbss) = Vector.splitAt ix (Vector.snoc bss bs)
+        (lacc, lpad) = padding 0    0 (Vector.map BS.length lbss)
+        (racc, rpad) = padding lacc 0 (Vector.map BS.length rbss)
       in
-        rpad
-
-    padding :: Int -> Int -> [Int] -> (Int, Int)
-    padding acc pad []       = (acc, pad)
-    padding acc pad (l : ls)
-      | acc + l + hEADER_LENGTH <= termLen = padding (acc + l + hEADER_LENGTH) pad ls
-      | otherwise                          = padding (l + hEADER_LENGTH)
-                                                         (pad + (termLen - acc)) ls
+        trace (unlines [ "PAD"
+                       , "ix: "   ++ show ix
+                       , "lbss: " ++ show (Vector.map encodeRunLength lbss)
+                       , "rbss: " ++ show (Vector.map encodeRunLength rbss)
+                       , "lacc: " ++ show lacc
+                       , "lpad: " ++ show lpad
+                       , "racc: " ++ show racc
+                       , "rpad: " ++ show rpad
+                       ])
+        (lpad, rpad)
+
+    padding :: Int -> Int -> Vector Int -> (Int, Int)
+    padding acc pad ls = case Vector.uncons ls of
+      Nothing -> (acc, pad)
+      Just (l, ls)
+        | acc + l + hEADER_LENGTH <= termLen -> padding (acc + l + hEADER_LENGTH) pad ls
+        | otherwise                          -> padding (l + hEADER_LENGTH)
+                                                        (pad + (termLen - acc)) ls
 
 readJournalFake :: FakeJournal -> (FakeJournal, Maybe ByteString)
 readJournalFake fj@(FakeJournal jour ix) =
@@ -353,7 +390,14 @@ unit_bug3 = assertProgram ""
   , ReadJournal
   , AppendBS [(32756,'N')]
   , ReadJournal
-  , AppendBS [(32756,'W')]
+  , AppendBS [(32756,'W')] -- 7+6 + 32756+6 + 32756+6 = 65537 which won't fit in
+                           -- the first term, so padding is written, term
+                           -- rotation happens, and the Ws get written to the
+                           -- next term. The padding will be pretty big:
+                           -- 65536-(7+6 + 32756+6) = 32761, so after the Ws are
+                           -- written there's 32761 + 32756+6 = 65523 unread
+                           -- bytes. 7+6+32756+6 = 32775 bytes have been read,
+                           -- so the limit is 32775 + (64*1024 / 2) = 65543.
   , AppendBS [(32756,'Q')]
   ]
 
@@ -361,6 +405,26 @@ unit_bug4 :: Assertion
 unit_bug4 = assertProgram ""
   [AppendBS [(1, 'A')], AppendBS [(32755,'Q')], AppendBS [(1,'D')]]
 
+unit_bug5 :: Assertion
+unit_bug5 = assertProgram ""
+  [AppendBS [(1,'K')], AppendBS [(32757,'Q')], ReadJournal, AppendBS [(32761,'R')]]
+-- ^ Before writing the Rs, we have posiiton: 1+6+32757+6 = 32770 and limit:
+-- 1+6+(64*1024/2) = 32775, so that's fine, however 32770+32761+6 = 65537 so it
+-- doesn't fit in the current term. 65536-(1+6+32757+6) = 32766 bytes of padding
+-- is written instead and then term rotation happens before the 32761+6 bytes
+-- related to the append of Rs, this gives us a position of 32770+32767 = 65537
+-- which is over the limit and so backpressure should happen.
+
+unit_bug6 :: Assertion
+unit_bug6 = assertProgram ""
+  [ AppendBS [(1,'J')], ReadJournal, AppendBS [(32757,'K')], AppendBS [(32761,'H')]
+  , AppendBS [(1,'F')]]
+
+unit_bug7 :: Assertion
+unit_bug7 = assertProgram ""
+  [AppendBS [(32756,'Y')], AppendBS [(32761,'A')], ReadJournal, AppendBS [(1,'J')]]
+
+
 ------------------------------------------------------------------------
 
 assertProgram :: String -> [Command] -> Assertion