Mounting external drive rendered unreadable and then came back

[snowboardjoe]

Running 6.12.6 here. A few weeks ago when I ran into a btrfs emergency I was using the restore command to copy the contents of that to an externally attached SSD (Samsung T7 and formatted as hfsplus). I was able to copy the contents of that restore there for safe keeping while I did my btrfs repairs. A week later I realized my external drive was not attached to my personal system (mac mini). I went to plug it in and it would not mount. It had power, but nothing could see it. I used Samsung Magician would could see it, but said there were no mountable systems. It knew there was data there, but could not do anything with it. I was rather stunned by this and thought maybe the drive died.

 

On a hunch, I took the drive and plugged it back into unraid and mounted it. All data was there (old and new data). Uh, ok, this is odd. It looks perfectly fine. Detached it from unraid and back into Mac mini and it mounted immediately as if nothing ever happened. All data was present as expected. Any thoughts on what might have happened here? Happy my data is fine, but very strange behavior. It's as if the first mount on unraid left the filesystem in some bad state, but repeating the operation set things straight again.