Sony FX30 HEVC (up to 4:2:2 10-bit) displays normally in an 8-bit Vegas project (current build), but the codec breaks immediately if you switch to 10-bit project mode. I can upload a short clip somewhere (?) if needed, but I'm guessing you won't have any trouble reproducing this.
Note that Sony XAVC clips from my RX100 also have issues in 10-bit mode, as described here:
by the way the FX30 is awesome (if you can get one)!