Hmm.. Starting with D - C as its first two moves, it will get in response from all TfT-based strategies a C - D Which means it will end up believing that other bots are likely to cooperate if it defects, and to defect if it cooperates. Which will be further boosted by the response in the third move (Defect), which will receive a (Cooperate) in response, thus further increasing its belief in the worth of defection. It seems likely to effectively become a defectbot in this manner.

On the other hand a C-D returns it a corresponding C-C, which followed by another D returns it a D; this seems more favourable for cooperation.