In that case, it is sadly a frankenwatch - someone has "married" parts from two different watches. This won't affect the functionality but it offends the purists and devalues the watch. Since neither of the original two watches the parts came from (one Chateau, one Mondaine) are particularly valuable or desirable, the depreciation is not that great in absolute terms. If it bugs you, get rid of the watch and buy another.
Hartmut Richter