diff --git a/makepanda/makepanda.py b/makepanda/makepanda.py
index b90c53ec24..e1d4dec612 100755
--- a/makepanda/makepanda.py
+++ b/makepanda/makepanda.py
@@ -366,6 +366,12 @@ if GetHost() == "darwin":
 if VERSION is None:
     # Take the value from the setup.cfg file.
     VERSION = GetMetadataValue('version')
+    match = re.match(r'^\d+\.\d+(\.\d+)+', VERSION)
+    if not match:
+        exit("Invalid version %s in setup.cfg, three digits are required" % (VERSION))
+    if WHLVERSION is None:
+        WHLVERSION = VERSION
+    VERSION = match.group()
 
 if WHLVERSION is None:
     WHLVERSION = VERSION
@@ -2684,11 +2690,18 @@ template class CheckPandaVersion<void>;
 
 
 def CreatePandaVersionFiles():
-    version1=int(VERSION.split(".")[0])
-    version2=int(VERSION.split(".")[1])
-    version3=int(VERSION.split(".")[2])
-    nversion=version1*1000000+version2*1000+version3
-    if (DISTRIBUTOR != "cmu"):
+    parts = VERSION.split(".", 2)
+    version1 = int(parts[0])
+    version2 = int(parts[1])
+    version3 = 0
+    if len(parts) > 2:
+        for c in parts[2]:
+            if c.isdigit():
+                version3 = version3 * 10 + ord(c) - 48
+            else:
+                break
+    nversion = version1 * 1000000 + version2 * 1000 + version3
+    if DISTRIBUTOR != "cmu":
         # Subtract 1 if we are not an official version.
         nversion -= 1
 
diff --git a/panda/src/gobj/geomVertexArrayData.cxx b/panda/src/gobj/geomVertexArrayData.cxx
index 9b07969e46..13f885280a 100644
--- a/panda/src/gobj/geomVertexArrayData.cxx
+++ b/panda/src/gobj/geomVertexArrayData.cxx
@@ -215,19 +215,24 @@ is_prepared(PreparedGraphicsObjects *prepared_objects) const {
 VertexBufferContext *GeomVertexArrayData::
 prepare_now(PreparedGraphicsObjects *prepared_objects,
             GraphicsStateGuardianBase *gsg) {
-  if (_contexts == nullptr) {
+  if (_contexts != nullptr) {
+    Contexts::const_iterator ci;
+    ci = _contexts->find(prepared_objects);
+    if (ci != _contexts->end()) {
+      return (*ci).second;
+    }
+  } else {
     _contexts = new Contexts;
   }
-  Contexts::const_iterator ci;
-  ci = _contexts->find(prepared_objects);
-  if (ci != _contexts->end()) {
-    return (*ci).second;
-  }
 
   VertexBufferContext *vbc = prepared_objects->prepare_vertex_buffer_now(this, gsg);
   if (vbc != nullptr) {
     (*_contexts)[prepared_objects] = vbc;
   }
+  else if (_contexts->empty()) {
+    delete _contexts;
+    _contexts = nullptr;
+  }
   return vbc;
 }
 
diff --git a/panda/src/gobj/shaderBuffer.cxx b/panda/src/gobj/shaderBuffer.cxx
index fa16293d4d..9164a870ae 100644
--- a/panda/src/gobj/shaderBuffer.cxx
+++ b/panda/src/gobj/shaderBuffer.cxx
@@ -76,19 +76,24 @@ is_prepared(PreparedGraphicsObjects *prepared_objects) const {
 BufferContext *ShaderBuffer::
 prepare_now(PreparedGraphicsObjects *prepared_objects,
             GraphicsStateGuardianBase *gsg) {
-  if (_contexts == nullptr) {
+  if (_contexts != nullptr) {
+    Contexts::const_iterator ci;
+    ci = _contexts->find(prepared_objects);
+    if (ci != _contexts->end()) {
+      return (*ci).second;
+    }
+  } else {
     _contexts = new Contexts;
   }
-  Contexts::const_iterator ci;
-  ci = _contexts->find(prepared_objects);
-  if (ci != _contexts->end()) {
-    return (*ci).second;
-  }
 
   BufferContext *vbc = prepared_objects->prepare_shader_buffer_now(this, gsg);
   if (vbc != nullptr) {
     (*_contexts)[prepared_objects] = vbc;
   }
+  else if (_contexts->empty()) {
+    delete _contexts;
+    _contexts = nullptr;
+  }
   return vbc;
 }