This is not particularly surprising since Collabora leverages the Open Document Format (ODF) rather than Microsoft's proprietary OOXML specification. Microsoft's specification has previously caused problems for other vendors like LibreOffice's The Document Foundation (TDF) too.

While it seems elections killed this initiative, the above is why I recommended EuroOffice or OnlyOffice for converts. It has a more MS feel and much, much better support for conversions.

I'm still confused why TDF hasn't put more time into opening other formats.