My Book Live Duo + RAID

Yea, this has been fixed long ago. But it never upstreamed to the stable releases 17.01.x releases.

See this thread:
RAID not working after Update LEDE 17.01.0 final GoFlexNetRAID not working after Update LEDE 17.01.0 final GoFlexNet

If you want raid* use the current master branch or wait for the next openwrt release.