"... This release primarily fixes a serious regression in 3.2.4. This regression does *not* cause any risk to data. It simply means that adding a device with "--add" would sometime fail when it should not. The fix also includes a couple of minor fixes such as making the "--layout=preserve" option to "--grow" work again. ..." Reproducible: Always
Perhaps related: https://bugs.gentoo.org/show_bug.cgi?id=416081
should be all set now in the tree; thanks for the report! Commit message: Version bump http://sources.gentoo.org/sys-fs/mdadm/mdadm-3.2.5.ebuild?rev=1.1