Possible conflict

Here is my problem. I own a park with a number of rentals. In general we have very few vancancies and my manger does a good job keeping the place full. I’ve acquired a number of units over the years ,mostly from tenants who had to sell. This year I decided I had a enough units and let my manager buy two units that became available .They had expressed an interest in buying a couple of units ,fixing them up and then renting them.

Well wouldn’t you know it there two units are rented a couple of mine are empty .

I doubt if this was intentional. It does bring up the question of priorities and who gets what.Given that I’m very happen with the manager and have no evidence of malfesance How do I handle this situation?