Hello,
I know I have earned multiple monuments and every so often I change them around. Today I earned a new one and I went to my garrison to display it and they all say “EMPTY” when trying to page through them. I have no active addons, Ive logged out and back in. Tried many things but still doesnt work. It also does the same for a few other people that I know tried.
I am in same situation and came here to see if anyone else reported this bug. I have multiple monuments and the display says “EMPTY”. I added level 3 garrison with my Dracthyr for xmas decorations and see the “EMPTY” on monuments. I loaded my panda alt and can see the monuments I had previously selected, but the display says “EMPTY” and does not allow me to change the monuments. I hope this is the correct place to mention the bug and replied to your post to show we are not alone.
Hey, I just completed my Dracthyr’s Level 3 Garrison and, as you have both stated, the monument stand just says ‘empty, empty, empty’ when I scroll through.
I have earned a lot of monuments for my Garrison, yet my Dracthyr is unable to use them.
(All my Allied Race Characters, who weren’t around during WoD either, are able to.)
I just opened my Garrison for my Boosted Human Rogue and this issue is happening with her as well.
Yeah, not many people probably notice this anymore but this is something that we earned and still earn so there should definitely be a fix for this.
I can’t even change the Monument on all my older characters who have had their Garrisons since WoD. 
I am having the same issue, but even worse, all three of my monuments I had displayed are gone!! Worse, I reached out to support and they just told me to come here… which is another obvious dead end, as no one from Blizzard appears to be addressing the issue.
Same issue. Are they not fixing this?