Unfortunately open3d never worked consistently well for us, causing many different problems especially in cross-platform. We have reimplemented the functionality in open3d as part of the ITK, and a new alpaca module called alpaca_preview is available in latest SlicerMorph. See this thread on how to enable it.
Going forward, this ITK based ALPACA will be default and we will stop using open3d. Our test how shown that ITK based implementation is in fact gives us slightly better results.
I suggest you start using the ITK-ALPACA (alpaca_preview) as well.