I did the second backup again and reattached the disk to my system, the result was like that:
https://5md.at/l/obcons2 (disk attached but CRC error follows) But I can mount it correctly. So I decide to try changing drive enclosure, from as a simple as not powered Orico 2.5'' to a powered Orico 2.5/3.5'': solved, disk attached, no CRC error. Three weeks ago I attached the second backup disk by the same not powered enclosure to recover some files and I got no problems at all but frankly speaking I do not remember if I checked the console status, probably not. It seems when two days ago I reported in misc, I got a clash of problems, by coincidence: a not successful backup and the wrong enclosure (a blasphemous two external not powered enclosures on a usb hub). This is all what I can interpret for you. The behaviour of OpenBSD with the CRC error popping up referencing sd1 (by the same UID) should be your part and it is all to understand. -- Daniele Bonini