This actually only happened after an e-mail server ran out of space due to run away log files. Normal Desktop clients were not affected. It appeared to be a bug in K9 mail but even reinstalling/wiping all settings did not fix it (read e-mails would still not reappear).
This is moreso a bug in Dovecot where it probably messes up the index files.
How do you fix this in Dovecot/your e-mail server?
You need to delete the do........
I separated the 2 drives in the RAID 1 array.
1 is the old one /dev/sda and is out of date, while the separated other one /dev/sdc was in another drive and mounted and used with more data (updated).
I wonder how mdadm will handle this:
usb-storage: device scan complete
md: md127 stopped.
md: md127: raid array is not clean -- starting background reconstruction
raid1: raid set md127 active with 1 out of 2 m........