Restrict cases where vertex buffer size from index buffer type is used (#3304)

Ryujinx.Graphics.Gpu/Engine/Threed/StateUpdater.cs

@@ -928,7 +928,7 @@ namespace Ryujinx.Graphics.Gpu.Engine.Threed
 
                     size = endAddress.Pack() - address + 1;
 
-                    if (stride > 0 && indexTypeSmall)
+                    if (stride > 0 && indexTypeSmall && _drawState.DrawIndexed && !instanced)
                     {
                         // If the index type is a small integer type, then we might be still able
                         // to reduce the vertex buffer size based on the maximum possible index value.