Here's what we know:
* Riza has been Roy's loyal aide for a long time. They have a deep, close relationship, built on mutual trust and respect.
* They are both highly competent and professional soldiers. They are focused on their duties and wouldn't act inappropriately in a professional setting.
* Their relationship is based on mutual respect and understanding. They value each other's abilities and have a strong professional bond.
While there are hints of romantic tension between them, their interactions are generally professional and their dynamic is one of respect and partnership.
Therefore, it's highly unlikely that Roy would act weird when first meeting Riza. They would have already known each other for a long time by that point.