I'm not aware of a bug with this, so to be clear:

Stage 6, Normal, Sewers of Arnoc and the boots look like this? (but lower rarity/rank/different set)

i

Yes. Stage 6, Normal, Sewers of Arnoc, and the boots look like the photo you attached but lower rarity/rank and it is the offence set of boots with ATK % as the primary stat

could you take a screenshot of those boots? thanks 

So I had sold all the boots from earlier so I did the mission again and this time oddly it finally worked and I got the reward for it and was able to move forward on the progress missions. It is now showing the next mission thankfully. Thanks for your time and assistance!

i

i

Odd, just maybe needed to turn off and restart the app. 

Glad it works though. :D

I have two alt accounts that have a similar problem to this,. Both are stuck at Campaign Mission

I have run multi-battle and got a chestplate with Atk % a number of times but it is not clearing and now getting a similar issue with a Gauntlet mission on another

i

Running stage 2-4 on Normal, getting attack% gauntlets to drop and it's not registering?