Hi Jerryuk,
All of the "Big Three" brands (PP, AP, VC) use some movements supplied by other manufacturers. That in itself is not terribly scandalous and quite thoroughly disected and documented on the various watch discussion forums. Whether or not it is an issue in general or in the specifics is largely a question of personal preference and priorities. The practice of purchasing movements from specialist manufacturers is so old and well established in the Swiss watch industry (dating back literally to the very beginning) that one is tempted to call it the traditional way that things are done.
Some of the folks that find it distasteful when brands use movements that are not 100% their own may also fault Blancpain for using Piguet movements. Piguet also manufactures movement for other brands and many of the Blancpain movements are not proprietary or exclusive (see the thread above about the 1185 and which other brands use it). Blancpain fans will generally counter with the fact that since Blancpain's resurrection in the early '80s they have worked very closely with Piguet and been either partly or wholly owned by the same persons/organizations as well. so much so that Piguet could be considered the manufacturing arm of Blancpain. Whether this argument holds water with you or is even important at all is of course also a matter of personal preference and priorities.
_john