diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 3273dc2..6635463 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -5631,6 +5631,9 @@ Node *firstGeqLogical(Node *n, const TrivialSpan key) {
           goto downLeftSpine;
         } else {
           n = nextSibling(n);
+          if (n == nullptr) {
+            return nullptr;
+          }
           goto downLeftSpine;
         }
       }
@@ -5928,7 +5931,9 @@ checkMaxVersion(Node *root, Node *node, InternalVersionT oldestVersion,
       expected = std::max(expected, child->entry.rangeVersion);
     }
   }
-  auto key = getSearchPath(root);
+  // Account for the range version of the first key after `node`'s subtree: a
+  // range write spanning the subtree is recorded there.
+  auto key = getSearchPath(node);
   bool ok;
   auto inc = strinc(key, ok);
   if (ok) {