Hi,
Since 1.8.1 and also in 1.8 (not that often though) my server keeps crashing with the error message:

[22:17:48] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 2342ms behind, skipping 46 tick(s)
[22:19:19] [Server Watchdog/FATAL]: A single server tick took 60.00 seconds (should be max 0.05)
[22:19:19] [Server Watchdog/FATAL]: Considering it to be crashed, server will forcibly shutdown.

i doubled the number of cores for the VM, also doubled the RAM and also changed the java version from openjdk to oracle; but it keeps crashing. there is no specific event inside the game that triggers the crash.
the server is not even close to overload. RAM usage is about 700MB and only 1 to 2 cores are used up by 50-80%.

I attached all crash logs from today.