Good afternoon frank3nstien,
The two events that you are looking at are very rare and only happen under certain circumstances.
Event ID 4: This triggers when the service state has changed. This will fire if you restart the service, shut it down, or any other actions that could be taken upon the service. If you want to find logs regarding this Event ID follow these steps.
While Sysmon is running, go to powershell and type in "services.msc". This will open the list of services currently running on your machine. Find Sysmon and select it. Then click restart. If you want more than one log, repeat the restart action multiple times. Now wait some time then check Splunk for Event ID 4.
Event ID 255: Error: I honestly do not know how to produce this event but again it is a rare event.
I hope this helps! Have a wonderful day!
Resources:
https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/default.aspx?i=j
