Years ago I posted about a large rework to where Collabora helped a customer to make Writer read the drawingML markup for DOCX shapes. You can read the various benefits of this switch in that article — but similar to other large reworks, this also broke some previously working corner-cases, where test coverage lacked.
One of these is charts in group shapes. This needs explicit handling, as Writer normally handles charts as TextEmbeddedObjects, while code that imports charts from OOXML is not specific to Writer. The fix just tells the generic drawingML import to use a Writer-specific service name for the charts.
This is available in LibreOffice master (towards 6.3).