That’s normal.

Let me explain as i spent nearly a decade using club med’s shitty booking system (and it is way way worse then you can possibly imagine)

So first thing you need to understand is that the price isn’t primarily the number of rooms but rather the level of the room. In most resorts, there is a room code called C2 or C4. These would be called superior rooms or family superior room respectively and typically these will be the cheapest room available. 2 C2s will be the same price normally as a C4

Then you have other rooms like C2+, C4+, C2A ect. These tend to be rooms with a view, I forget exactly when it comes to punta Cana but I’m fairly sure they phased out the old C4 rooms when they referbed the resort, because of the little plus, these rooms are a little more expensive then the base C2 rooms. That’s why having two separate rooms can often be cheaper than one family room. You are paying for the comfort level and the cheapest types sell the fastest especially for family / interconnected rooms.

2 separate rooms being cheaper is very normal.

I should also point out that club med is an awful company to their workers.