All my addons are turned off. I can no longer see guild tags from other people.
Social settings has all names on. Still nothing.
Last, I used the addon AdvancedInterfaceOptions, guild names is checked but does nothing as well.
Would like this resolved.
You may have corrupted UI settings. As an experiment, try a UI reset as described here;
This is reversible if needed, but if the reset fixes the problem you’ll have to either rebuild your preferences and addons based on the reset (default) UI or restore the corrupted UI and live with the display bug.