Curtain walls keep reference the original level after redefining its base and top constraints to a different level.
After drawing a curtain wall and redefining its base and top constraints to different levels, when copying that curtain wall and pasting it aligned to different levels, Revit keeps pasting it with reference to the original level. In addition, when creating a model group including that curtain wall, the reference level of the group is defined as the original level of the curtain wall.
[b]Steps to Reproduce[/b]
1. Draw a curtain wall on Level 1 with top constraint at Level 2.
2. Redefine its constraints as Level 3 for the base and Level 4 for the top.
3. Copy the curtain wall and paste it aligned to the Level 5. Curtain wall is pasted aligned to Level 7, instead of Level 5.
4. Create a group from the curtain wall at Level 3. Check the Reference Level of the group. It is Level 1 (the original level of the curtain wall).
Revit2019.2.1