The logs are not showing the exact culprit, but I suspect a mod is causing the issue. Probably by deleting a property entirely instead of setting to 0 or ''.
See if you can get into Reserve with no mods and a fresh profile, if so you will need to go through your mods and do a bit of experimentation to find the culprit.
File
Kiki-AllTheBoss 2.6.3

Added config option randomizeBossZonesEachRaid: When keepOriginalBossZones = false, Each boss gets set a single spawn zone, and the bosses are spread over the map. If randomizeBossZonesEachRaid is set to true then every time you complete a raid, the zone that each boss is assigned will be reselected. This will make make the locations each boss spawns different every raid. (true / false)