This isn't a personal issue and is a new patch feature which was working in patch 1.18a till now. No one in and out of game has gotten /display main on or /display main off to work at all and haven't seen this issue reported yet. It's simply not implemented either at all or not properly! If the wording for said command in game was changed it should be reflected in patch notes but so far no one has been able to get it to work or figure out a working command for this feature.