By how much are they moving? Can you post some screenshots to illustrate this problem?

Hi Andy. Thanks for getting back to me. They dont move much, but they do, and all of them at that... Usually, they move by up to half a grid, either up, down, sideways, or both. What really bothers me, is that I can't seem to be able to reproduce the effect and the conditions for such behaviour are not clear to me. Only saving and reopening seems to be the common action to these situations, but not all the time. In addition, some pads lose their connection with their pads/holes, some don't (even though they share the same Net). This leads me to say that the behaviour originates from the placement of the pads during the reconstruction of the PCB from file during the opening process, but I could be wrong. My grid parameters are as follows: Grid size: 1.27mm Snap size: 0.125mm Alt Snap: 0.063mm 

Some before and after screenshots might be more illuminating. Maybe with the difference marked for clarity? Could you make this project public and share the link to the project?

Hi Not really understand the problem, can you provide the previou images and abnormal images for comparing?