I've had my Unlocked Coral Blue GS8+ since end of July and it's still going strong. No software issues or weird shenanigans. I attribute a lot of that to being on the Unlocked 955U1 firmware. I still kept my 935U Galaxy S7 Edge and it too is going strong on the Unlocked firmware.
I think most of these issues are coming from Sprint messing with the ROM too much with their bloat and other crap.
The only issue I've had so far was when Google updated their Google app, my battery began to drain a lot faster - ~5%/hr instead of the normal ~2%/hr. A simple reboot took care of that. Google is still my NUMBER ONE enemy for battery life. I"m hoping Oreo will take care of Google.
Now the power supply for our MB has seemingly failed. When I first plugged it in, I thought the power supply seemed overly ‘noisy’ in that it made a constant hiss/buzz. Woke up this morning to 2 bars of 1x, and the MB indicated it needed to be plugged in. Receptacle tested fine. Power Supply no longer makes any noise and smells a little suspect so Sprint is sending a replacement.
I'm thinking they've closed off residential requests for now until they fill some of the orders. I know the link is around here somewhere, Google Sprint magic box, or try sprint.com/magicbox
Currently, last I heard, it was business only...