Hi,
I have received some help from our Technical Support team regarding this issue.
The Element Settings dialog shows IFC properties only based on the IFC Translator set as Preview (
https://helpcenter.graphisoft.com/user-guide/77315#XREF_54713_Preview_Translator). This means that properties can be missing from here and can have different values (based on a different mapping rule).
In this situation, since you have the IFC output correct but the value displayed in the Settings dialog is not, this could be the cause. I would suggest changing the Preview IFC Translator to that one that you use to export. That way, the value will show the correct information.
I hope this will help you with the issue! Should you have any further questions feel free to ask me again. Thank you very much!
Best regards,
Minh
Minh Nguyen
Technical Support Engineer
GRAPHISOFT