I tested this myself on a siptah server (no mods). I can confirm your findings:
Test1:
- Server offline.
- Set settings:
PVPBuildingDamageEnabledSunday=True
PVPBuildingDamageTimeSundayStart=1600
PVPBuildingDamageTimeSundayEnd=2200 - Start server and log in, see times read 0000-2200.
Test2:
- Server online
- Open the server settings in-game.
- Set start to 13:00 and end to 21:00
- Check the ServerSettings.ini, note that 2100 was updated correctly but the start still reads 1600 in your .ini file which is your old value from Test1.
- Restart the server, check again. Note your ServerSettings.ini still reads 1600 for start but your in-game menu shows 00:00.
Furthermore, Ignasis mentioned that they are investigating: