Binding GridGroupingControl to DataTable with SqlTypes columns hangs

I've used GridGroupingContol(4.102.0.50) binding it to the the DataTable with columns of primitive .NET types (int, double, string). Recently because of need to support nullable values I tried switching to types from SqlTypes namespace. And I'm facing strange behavior - when Grid loads it hangs all application and eat memry very fast. Would you please suggest how to get it working.

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