Well, after some additional testing I should say:
- looks like our server is keeping last loaded chunks for all players until next restart.
- Thats mean after the player is log-off, server still will keep 84 or so chunks “for him”
- server will remember which chunks was loaded for player even after restart, but
- after the server restart it will keep such chunks only for ~hour, after that, finally, those chunks will be unload, and all processes will stop
- This player-“reserved”-chunk-loading does not logged anywhere(like forcedchunks.dat)
And because we usually restart server only when someone at the base(thats strange, i agree) so we had an illusion of “always loaded field around”
So i think we are done here