Added this line so 1000 per second bots wouldn't crash server, but sometimes server crash with this error randomly not from bots, how to fix it?

Added line in:
https://cdn.discordapp.com/attachments/241667244927483904/539473496758157333/unknown.png

Crash error:
https://pastebin.com/qK40VDb2

The exception itself (it's not a crash) should be resolved in the latest version.

As for dealing with bot attacks, I don't see that as being a LP problem. It will load user data for any user who connects, as you would expect.

Either you need to get an anti-bot plugin which can cancel the connections before they are handled by plugins on the server, or enable online mode and let Mojang do that for you.

Haven't been fixed even without that line. Can you please try catch that error, so it wouldn't crash server?

[15:57:27] [Server thread/ERROR]: Encountered an unexpected exception java.util.NoSuchElementException at java.util.concurrent.ConcurrentSkipListMap$Iter.advance(ConcurrentSkipListMap.java:2316) ~[?:1.8.0_201] at java.util.concurrent.ConcurrentSkipListMap$KeyIterator.next(ConcurrentSkipListMap.java:2351) ~[?:1.8.0_201] at com.google.common.collect.AbstractMapBasedMultimap$Itr.next(AbstractMapBasedMultimap.java:1150) ~[spigot-1.8.8-8.jar:git-Spigot-21fe707-e1ebe52] at java.util.Collection.removeIf(Collection.java:414) ~[?:1.8.0_201] at me.lucko.luckperms.common.model.NodeMap.removeIf(NodeMap.java:244) ~[?:?] at me.lucko.luckperms.common.model.PermissionHolder.removeIfTransient(PermissionHolder.java:314) ~[?:?] at me.lucko.luckperms.bukkit.inject.permissible.LPPermissionAttachment.clearInternal(LPPermissionAttachment.java:208) ~[?:?] at me.lucko.luckperms.bukkit.inject.permissible.LPPermissionAttachment.remove(LPPermissionAttachment.java:218) ~[?:?] at java.util.concurrent.ConcurrentHashMap$KeySetView.forEach(ConcurrentHashMap.java:4649) ~[?:1.8.0_201] at me.lucko.luckperms.bukkit.inject.permissible.LPPermissible.clearPermissions(LPPermissible.java:305) ~[?:?] at org.bukkit.craftbukkit.v1_8_R3.entity.CraftPlayer.disconnect(CraftPlayer.java:1135) ~[spigot-1.8.8-8.jar:git-Spigot-21fe707-e1ebe52] at net.minecraft.server.v1_8_R3.PlayerList.disconnect(PlayerList.java:349) ~[spigot-1.8.8-8.jar:git-Spigot-21fe707-e1ebe52] at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java:871) ~[spigot-1.8.8-8.jar:git-Spigot-21fe707-e1ebe52] at net.minecraft.server.v1_8_R3.NetworkManager.l(NetworkManager.java:314) ~[spigot-1.8.8-8.jar:git-Spigot-21fe707-e1ebe52] at net.minecraft.server.v1_8_R3.ServerConnection.c(ServerConnection.java:145) ~[spigot-1.8.8-8.jar:git-Spigot-21fe707-e1ebe52] at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:814) ~[spigot-1.8.8-8.jar:git-Spigot-21fe707-e1ebe52] at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) ~[spigot-1.8.8-8.jar:git-Spigot-21fe707-e1ebe52] at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) ~[spigot-1.8.8-8.jar:git-Spigot-21fe707-e1ebe52] at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [spigot-1.8.8-8.jar:git-Spigot-21fe707-e1ebe52] at java.lang.Thread.run(Thread.java:748) [?:1.8.0_201] [15:57:27] [Server thread/ERROR]: This crash report has been saved to: /root/mc/./crash-reports/crash-2019-02-03_15.57.27-server.txt [15:57:27] [Server thread/INFO]: Stopping server

Moving discussion to #1416 - please don't open duplicate issues in the future, much easier to just keep everything in one place..