Guild Waystone stash tab not synching properly?

Me and a guildmate noticed that sometimes when one of us places waystones into the guild waystone tab, the other can not see them.

It can be fixed for now by the person not seeing the waystones restarting the game/changing character.
The bug seems to happen when the other person is interacting with the waystone tab while someone else is placing waystones in the tab at the same time?