From this Q&A;: Revit Reader - IFCPlate
It seems that this question is the same case as C130891 (PR#69269) I reported this Sept.
Could you please check this? @DaveAtSafe
I heard that this issue is planned to be fixed in FME 2018, but it doesn't seem to be implemented yet in the latest beta build 18213. It's a critical issue for a customer, and they (and I) wait for 2018 release.
Hope it will be definitely fixed by 2018 official release. Thanks in advance.