Chat sometimes doesn't work on Realms

Since the last update, Minecraft chat sometimes no longer works on my realms. The only way to fix this is to restore a previous backup without this bug and hope that the bug doesn't occur again. It is possible to use the msg/tell function, but not the public chat or commands like /say and /tellraw. I haven't found a trigger for this bug, it has already occurred on 2 different realms of mine.