I was reading through your post, and honestly although I see some SMART issues this should not have any effect on the disk itself. My only advise is to try and zero out at least the first few hundred megabytes across the disk, and try formatting it again on EXT4 using the web GUI. I've seen my own share of odd behaviors when there was data already present on the drive.
I will try but these HDD are brand new, with no data on it.
In the mean time, this morning I started the NAS, it was shut down for a few days, didn'd had time for it, and in stead of booting, OMV just showed me this message:
What should I do. The SD card I use is a 16 GB SanDisk extreme brand new so it should be reliable.