First of all, thank you for joining our forum.
I’m sorry no one answered your posting. Please keep in mind that this is all voluntary support, once in a while some of the iXsystems employees will jump in and toss out some good information but that is the exception, it is mostly just us little guys out here trying to help out.
I only just saw this posting so I guess late is better than never.
If a SMART Short or Long test fails, the drive is bad regardless of any other testing.
As to why badblocks passed it, I can’t say definitively, but I do not see the results for all four test patterns. Maybe you received those but you did use “random” and looks like just the one test pattern, which was random. I realise badblocks takes a long time to test, especially with large capacity drives but if you are to use it as a tool in the future, I would recommend using all four test patterns. There is a reason it isn’t just one test pattern and it has to do with how the data is recorded to the drive, the magnetic flux changes to ensure it can faithfully write each possible variation. But I applaud you for taking action. You tried to diagnose the failure.
Next time please post the model of the drive, it would have helped just to round out the data, and that goes for any problem. Include the hardware specs (most is already in your posts at the bottom).