I am also having this problem. It appears my commander tag will only show in low population zones. As soon as I zone back to LA or anywhere busy the tag will disappear.
I am also having trouble switching which guild I am representing, I will click ‘represent’ but nothing will happen. I have to guest to a different server just to switch guilds. The same often works for my commander tag but when I come back to my server it disappears again.
I am also someone who is not actually in North America on a North American server (Stormbluff Isle).
A lot of people in my guild have noticed our server being particularly laggy lately and I just put it down to this. It has only been happening the past few days but it is still incredibly frustrating not being able to use my commander tag.
I hope this issue gets fixed soon.