diff --git a/doc/move.qbk b/doc/move.qbk
index ec67b0c..52156e9 100644
--- a/doc/move.qbk
+++ b/doc/move.qbk
@@ -802,6 +802,13 @@ Special thanks to:
 
 [section:release_notes Release Notes]
 
+[section:release_notes_boost_1_78 Boost 1.78 Release]
+
+*  Fixed bugs:
+   *  [@https://github.com/boostorg/move/issues/45 Git Issue #45: ['"Sort/merge bugs that affect boost::container::flat_map"]].
+
+[endsect]
+
 [section:release_notes_boost_1_77 Boost 1.77 Release]
 
 *  Fixed bugs:
diff --git a/include/boost/move/algo/adaptive_sort.hpp b/include/boost/move/algo/adaptive_sort.hpp
index 48403bb..ab72d28 100644
--- a/include/boost/move/algo/adaptive_sort.hpp
+++ b/include/boost/move/algo/adaptive_sort.hpp
@@ -453,9 +453,9 @@ bool adaptive_sort_build_params
          l_build_buf = size_type(l_intbuf*2);
          n_keys = l_intbuf;
       }
-      else if(collected == (n_min_ideal_keys+l_intbuf)){ 
+      else if(collected >= (n_min_ideal_keys+l_intbuf)){ 
          l_build_buf = l_intbuf;
-         n_keys = n_min_ideal_keys;
+         n_keys = size_type(collected - l_intbuf);
       }
       //If collected keys are not enough, try to fix n_keys and l_intbuf. If no fix
       //is possible (due to very low unique keys), then go to a slow sort based on rotations.
diff --git a/include/boost/move/algo/detail/merge.hpp b/include/boost/move/algo/detail/merge.hpp
index 6520655..0491fa0 100644
--- a/include/boost/move/algo/detail/merge.hpp
+++ b/include/boost/move/algo/detail/merge.hpp
@@ -863,49 +863,48 @@ template<typename BidirectionalIterator,
    typedef typename iterator_traits<BidirectionalIterator>::size_type size_type;
    //trivial cases
    if (!len2 || !len1) {
-      return;
+      // no-op
    }
-   else if (len1 <= buffer_size || len2 <= buffer_size)
-   {
+   else if (len1 <= buffer_size || len2 <= buffer_size) {
       range_xbuf<Pointer, size_type, move_op> rxbuf(buffer, buffer + buffer_size);
       buffered_merge(first, middle, last, comp, rxbuf);
    }
    else if (size_type(len1 + len2) == 2u) {
       if (comp(*middle, *first))
          adl_move_swap(*first, *middle);
-      return;
    }
    else if (size_type(len1 + len2) < MergeBufferlessONLogNRotationThreshold) {
       merge_bufferless_ON2(first, middle, last, comp);
-      return;
    }
-   BidirectionalIterator first_cut = first;
-   BidirectionalIterator second_cut = middle;
-   size_type len11 = 0;
-   size_type len22 = 0;
-   if (len1 > len2)  //(len1 < len2)
-   {
-      len11 = len1 / 2;
-      first_cut += len11;
-      second_cut = boost::movelib::lower_bound(middle, last, *first_cut, comp);
-      len22 = size_type(second_cut - middle);
+   else {
+      BidirectionalIterator first_cut = first;
+      BidirectionalIterator second_cut = middle;
+      size_type len11 = 0;
+      size_type len22 = 0;
+      if (len1 > len2)  //(len1 < len2)
+      {
+         len11 = len1 / 2;
+         first_cut += len11;
+         second_cut = boost::movelib::lower_bound(middle, last, *first_cut, comp);
+         len22 = size_type(second_cut - middle);
+      }
+      else
+      {
+         len22 = len2 / 2;
+         second_cut += len22;
+         first_cut = boost::movelib::upper_bound(first, middle, *second_cut, comp);
+         len11 = size_type(first_cut - first);
+      }
+
+      BidirectionalIterator new_middle
+         = rotate_adaptive(first_cut, middle, second_cut,
+            size_type(len1 - len11), len22, buffer,
+            buffer_size);
+      merge_adaptive_ONlogN_recursive(first, first_cut, new_middle, len11,
+         len22, buffer, buffer_size, comp);
+      merge_adaptive_ONlogN_recursive(new_middle, second_cut, last,
+         size_type(len1 - len11), size_type(len2 - len22), buffer, buffer_size, comp);
    }
-   else
-   {
-      len22 = len2 / 2;
-      second_cut += len22;
-      first_cut = boost::movelib::upper_bound(first, middle, *second_cut, comp);
-      len11 = size_type(first_cut - first);
-   }
-
-   BidirectionalIterator new_middle
-      = rotate_adaptive(first_cut, middle, second_cut,
-         size_type(len1 - len11), len22, buffer,
-         buffer_size);
-   merge_adaptive_ONlogN_recursive(first, first_cut, new_middle, len11,
-      len22, buffer, buffer_size, comp);
-   merge_adaptive_ONlogN_recursive(new_middle, second_cut, last,
-      size_type(len1 - len11), size_type(len2 - len22), buffer, buffer_size, comp);
 }
 
 
diff --git a/test/adaptive_sort_test.cpp b/test/adaptive_sort_test.cpp
index 512138b..454c4fe 100644
--- a/test/adaptive_sort_test.cpp
+++ b/test/adaptive_sort_test.cpp
@@ -74,9 +74,15 @@ int main()
    instantiate_smalldiff_iterators();
 
    const std::size_t NIter = 100;
-   test_random_shuffled<order_move_type>(10001, 3,   NIter);
-   test_random_shuffled<order_move_type>(10001, 65,   NIter);
-   test_random_shuffled<order_move_type>(10001, 101,  NIter);
+   //Below absolute minimal unique values
+   test_random_shuffled<order_move_type>(10001, 3,   NIter);   
+   //Above absolute minimal unique values, below internal buffer
+   test_random_shuffled<order_move_type>(10001, 65,   NIter);  
+   //Enough keys for internal buffer but below minimal keys
+   test_random_shuffled<order_move_type>(10001, 101,  NIter);  
+   //Enough keys for internal buffer and above minimal keys
+   test_random_shuffled<order_move_type>(10001, 200,  NIter);  
+   //Enough keys for internal buffer, and full keys
    test_random_shuffled<order_move_type>(10001, 1023, NIter);
    test_random_shuffled<order_move_type>(10001, 4095, NIter);
    test_random_shuffled<order_move_type>(10001, 0,    NIter);