Version 023 has non consistent behaviour regarding mdadm and lvm: i have DRACUT_MODULES="", but /boot/initramfs.img has '/sbin/dmsetup' and '/lib64/libdevmapper.so.1.02' because sys-fs/lvm2-2.02.88 is installed and '/usr/lib64/dracut/modules.d/95udev-rules/59-persistent-storage.rules' ('/etc/udev/rules.d/59-persistent-storage.rules' in initramfs) wants dmsetup and mdadm. Please split 59-persistent-storage.rules to 59-persistent-storage-lvm.rules, 59-persistent-storage-md.rules, etc and install only parts for enabled modules. I did not have such problem with dracut-022-r5.
I agree it would be a good idea to split rules file.
sys-kernel/dracut-024-r2 does not install /lib64/libdevmapper.so.1.02 and /sbin/dmsetup to initramfs.img
Seems dracut-027-r1 does not have this bug, but please recheck.
Upstream commit c46cda8260a53884182a9c8ad06f59e56729bdb4
It is present in 027 which is in the tree, therefore RESO FIXED. Thank you for the notice.