Bastien:
yes, I can reproduce the bug using capmove.el with the latest master. It is less salient in the small file that capmove makes, but very obvious in big files where you get to a completely different place after capture finished.
Description of the steps:
1. open the same org file in two frames
2. make sure the positions in those frames are different
3. try to capture something from one of those frames
4. after capture finished, the positions in those frames become the same, i.e. the frame where capture was invoked copied the position from another frame and lost its context that was there before capture.
Best,
Alex