Why are these unique ID objects appearing twice in a schedule?

[Kelly at Kanvi Homes]

We have an issue with correct surface area in one of our schedules. There are 2 walls with stone in this project but they are each appearing in the schedule twice. Does anyone know why that would happen? I've attached a pic of the scheme settings and of the schedule which clearly shows the unique ID of both objects appearing twice. Thanks in advance,

[brakpanpolisie]

I had a similar issue only with roofs over here : https://community.graphisoft.com/t5/Document-Visualize-forum/Excel-Import-Element-is-duplicated-in-S...

For interest sake what kind of wall is it? Composite, complex profile etc?

[Kelly at Kanvi Homes]

It's a composite wall, but with only one building material in it.

[Miha Nahtigal]

Your schedule should be of "Elements" type, not of "Surfaces"

[Kelly at Kanvi Homes]

I created a new elements schedule and it appears to be working correctly now. That still doesn't explain why the same unique ID object appears twice in one schedule.

[Laszlo Nagy]

I guess because the Wall has two sides and both sides are considered as individual surfaces in the Surface Schedule.

[Kelly at Kanvi Homes]

Also, I made a copy of the AC file and now the original surface schedule does not have duplicate items in it. Seems to be a bug in the original AC file???