Roundtrip Trouble: Resolve to FCPX

When I import the XML from Resolve, many videos in FCPX are black, and when revealed in finder, have a completely different duration.

About the workflow:

-shot with BMPCC, RAW video 25fps, additional material 29,97fps (Casio camera, H264) and 50fps (GoPro, ProTune).

-import all material in Resolve, export proxies using the roundtrip option.

-import XML in FCPX, edit material, many of which in multicam

-export XML in FCPX, 1.4

-import XML in Resolve, all material shows up. Grade and export to FCPX (tried both ProRes HQ and ProRes).

-import XML in FCPX... Fail. At first sight the timeline seems OK but audio isn't there, and some clips show up as compound clips. Many clips are black and those clips have a different duration, if revealed in finder.

Please enlighten me, what am I doing wrong here?