Personal story reward issue.
I can’t say I paid any attention to the ring when I got it (none of them gave the stats I used) so I can’t say if my ring had the same issue.
HOWEVER I think I can see where the problem lies, the gem that is meant to go into them has a higher level requirement (level 50+) than the ring (level 46) itself thus normally wouldn’t be able to be slotted (hence why you can’t slot your bought gem into it).
Leaves the question of: Should and do these rings come with a gem of a higher quality than normally allowed slotted and if so why didn’t yours.
Could be they made some small change that either altered the level of the ring or gem or something else a bit screwy if they are meant to have that gem.