super slow reshape speed after power failure

Currently I am converting my 6x 2tb raid5 from 256 chunk down to 4k.
While the reshape was running it was running around 4mb/s, which is
slow to begin with.

Yesterday we lost power and afte the system came back up, I was able
to bring the raid back up and running via 'export
MDADM_GROW_ALLOW_OLD=1`. The current issue is that the reshape is
running with only 700kb/s.

Any ideas?

Alex