memory leak when using region.put

I am seeing a weird behaviour when using the c# gemfire client. I am seeing memory leak on both the key and value when putting them into the region.

After further investigation, i note that the GCHandle created in the SafeM2UMConvert() is not properly released. However amazingly, when i set both the value and key to null (note the commented line), both the key and value are correctly garbage-collected. Wonder if anyone can provide a explanation of this behaviour?

** i would think that both key and value will be removed upon gc, which isn't the case either. I tried to call gc.collect after put but it does not help.

Here is a bit on the implementation,

function Add()

{

     lock(sync)

     {
          var key = new Key();
          var value = new Value(key);
          Region.Put(key, value);

          //key = null;

          //value = null; these 2 lines did the magic
}

[Serializable]

public class Key: IEquatable<Key>, IGFSerializable

[Serializable]

public class Value : IGFSerializable, IEquatable<Value>

Here is a bit of the call stack where the handler is created (i used the .net momory profiler to obtain this),
mscorlib!System.Runtime.InteropServices.GCHandle..ctor( object,GCHandleType )
mscorlib!System.Runtime.InteropServices.GCHandle.Alloc( object )
GemStone.GemFire.Cache!<Module>.gemfire.ManagedCacheableKey.{ctor}( ManagedCacheableKey*,IGFSerializable )
GemStone.GemFire.Cache!<Module>.GemStone.GemFire.Cache.?A0xa28d4856.SafeM2UMConvert<struct GemStone::GemFire::Cache::IGFSerializable,class gemfire::ManagedCacheableKey,class gemfire::Serializable,class GemStone::GemFire::Cache::Serializable>( IGFSerializable )
GemStone.GemFire.Cache!GemStone.GemFire.Cache.Region.Put( ICacheableKey,IGFSerializable,IGFSerializable )
GemStone.GemFire.Cache!GemStone.GemFire.Cache.Region.Put( ICacheableKey,IGFSerializable )
Add()