Do not optimize animated shapes (bug #3950)

CHANGELOG.md

@@ -20,6 +20,7 @@
     Bug #3876: Landscape texture painting is misaligned
     Bug #3897: Have Goodbye give all choices the effects of Goodbye
     Bug #3911: [macOS] Typing in the "Content List name" dialog box produces double characters
+    Bug #3950: FLATTEN_STATIC_TRANSFORMS optimization breaks animated collision shapes
     Bug #3993: Terrain texture blending map is not upscaled
     Bug #3997: Almalexia doesn't pace
     Bug #4036: Weird behaviour of AI packages if package target has non-unique ID

components/nifosg/nifloader.cpp

@@ -547,6 +547,11 @@ namespace NifOsg
                 node->setDataVariance(osg::Object::DYNAMIC);
             }
 
+            if (nifNode->recType == Nif::RC_NiTriShape && isAnimated) // the same thing for animated NiTriShapes
+            {
+                node->setDataVariance(osg::Object::DYNAMIC);
+            }
+
             osg::ref_ptr<SceneUtil::CompositeStateSetUpdater> composite = new SceneUtil::CompositeStateSetUpdater;
 
             applyNodeProperties(nifNode, node, composite, imageManager, boundTextures, animflags);