I work in multi-bodies, and at least for this current project I am experiencing an issue.
When I extrude something and merge it, picking only one bodies in the feature scope it is merging to "all bodies". If I go back in and edit the feature the "all bodies" radio button has been picked, if I then pick the "selected body" radio button and pick the one body I actually want to merge with, it works correctly.
using 2012 SP 4.0 Win 7x64
Is this a know bug at times? Other files have work properly.