Ai Wander start time resets when saving/loading the game
https://github.com/OpenMW/openmw/blob/master/apps/openmw/mwmechanics/aiwander.cpp#L205
https://github.com/OpenMW/openmw/blob/master/apps/openmw/mwmechanics/aiwander.cpp#L958
(RM-3412 from redmine: created on 2016-05-29 by scrawl ., , closed on 2016-08-04 by R. D.)