/trigger rarely works in multiplayer

When on my snapshot server with a friend, we were using a /tellraw to let players use the /trigger command. However, almost every single time, we were told the trigger wasn't enabled, even though we had a command block enabling the trigger for all players constantly.

Even after testing the command without the tellraw, we were still told the trigger wasn't enabled, which was, after checking the scoreboard.dat, simply not true.