Did some more work reproducing this bug I can reproduce it on large and huge maps only, standard = no problem. If I wait a turn before doing anything, again, no problem THEORY: Might be related to changing the los (or maybe movement costs) within the initial city radius. Going to try to verify that by moving my settler on turn 1, but duplicating the initial terrain at it's new location. EDIT: Verified. Move my settler 2 tiles, and duplicated the terrain initially around the settler at it's new location.