This behavior is not a bug. I first discovered it in C1-v6 when using local adjustment layers. I submitted a case to Phase One and here is their response-
This is correct.
By using the Local Adjustment tool and editing the color, a larger color space needs to be selected to accomidate the changes. Currently, when using this tool in this way the sRGB color space is used by default. This will be adjusted in the future but at present, given the infancy of the Local Adjustement tool, this is the proper way for the tool to correct for color in a selective manner.
Phase One Support
Since it has not been changed yet you may wish to open a case of your own. I, however, have not missed the "embedded camera profile" using the recent C1 releases. Prophoto has suited me.m YMMV.