org.bukkit.block.Sign s = (Sign) new Location(Bukkit.getWorld("world"), 0, 72, 0).getBlock().getState(); s.setLine(0, "TestLine"); s.update(true); //does not send update to client -> client has to rejoin
This issue appeared between first 1.16.2 arrival and the latest update.
Fixed with
https://hub.spigotmc.org/stash/projects/SPIGOT/repos/craftbukkit/commits/9a9c2234a4fba5bfbd91e20cc866eb3ba9224c7b