When trying to export any file to IFC then It is often seen that some properties go missing. It is because the configuration variable does not set properly,
Please follow the below information to get rid of this,
Go to the workset.cfg file of that particular workout (where you want to export the IFC) and open it in Notepad++. Then at the bottom of it, you will find this (see the screenshot), Here set the ‘IFC_WORKSET: ‘ value to ‘2’. Then save that configuration file. After doing so reopen OpenBuildings Designer. Then you will file the COBie properties are exported to IFC without any issue.