1.14 Vanilla Server Lag / World generation problem.

Hello,

I want to inform you that with Vanilla Minecraft 1.14 servers have a problem with generation. All servers of Vanilla Minecraft 1.14 have 20000+ms This problem is not with my machines. I tried with 4 other machines and the problem is global with 1.14. I asked other hosting companies and they have the same problem with Vanilla Minecraft 1.14 servers

• On other versions like Vanilla Minecraft 1.13.X there is no such this problem.

Console errors:
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[Server] Server thread/WARN Can't keep up! Is the server overloaded? Running 19877ms or 397 ticks behind
[Server] Server thread/WARN Can't keep up! Is the server overloaded? Running 16605ms or 332 ticks behind

Crash report:
**

---- Minecraft Crash Report -------- Minecraft Crash Report ----// Everything's going to plan. No, really, that was supposed to happen.
Time: 5/6/19 10:50 PMDescription: Exception ticking world
java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:909) at java.util.ArrayList$Itr.next(ArrayList.java:859) at net.minecraft.server.v1_14_R1.TickListServer.a(TickListServer.java:72) at net.minecraft.server.v1_14_R1.WorldServer.doTick(WorldServer.java:271) at net.minecraft.server.v1_14_R1.MinecraftServer.b(MinecraftServer.java:1054) at net.minecraft.server.v1_14_R1.DedicatedServer.b(DedicatedServer.java:396) at net.minecraft.server.v1_14_R1.MinecraftServer.a(MinecraftServer.java:953) at net.minecraft.server.v1_14_R1.MinecraftServer.run(MinecraftServer.java:798) at java.lang.Thread.run(Thread.java:748)

A detailed walkthrough of the error, its code path and all known details is as follows:---------------------------------------------------------------------------------------
– Head --Thread: Server threadStacktrace: at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:909) at java.util.ArrayList$Itr.next(ArrayList.java:859) at net.minecraft.server.v1_14_R1.TickListServer.a(TickListServer.java:72) at net.minecraft.server.v1_14_R1.WorldServer.doTick(WorldServer.java:271)

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Server type: Vanilla
Server RAM: 8GB
Server CPU: 4 Cores / 8 Threads
Players slots: 50
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Server from OVH:
OS: CentOS 7
Java version: 1.8.0_212
RAM: 64GB
CPU: 4 Cores / 8 Threads - Intel Core i7-7700K OC 4.5GHz
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