Group members had to be "moved to the project."

[gsucciZ65UY]

Hello,

I am getting this error, randomly, when working on some units (model groups).

When I get this, I have hide the model group, delete the elements which were moved to the project, turn the group back on, and do a restore all excluded to get back those elements.

Beside a waste of time, some units will have elements carefully excluded, so I cannot even do this process but I will have to restore one by one all elements effected by the error.

What is causing this?  why some groups never produce this, some groups move a few walls to the project, and one group actually moved most walls to the project.

thank you

[SteveKStafford]

Are these walls assigned to a level above for top constraint? Are there ceilings or hosted elements that are aligned/locked to them? I'd look for any dependency that Revit is attempting to maintain in the group definition. I'd also compare the group definition against the instances of the group, see if elements have been hidden in the instance of the group(s).

[syman2000]

  It is hard to know unless we know what goes on inside the group. One thing to check is if you have room boundary lines added to the group or you have linebase families added inside the group. If you add those walls, it will cause the wall to move to the project.