There might have even been the occasional purposeful burning to remedy “sick village syndrome”.
Move everyone out to temp housing during good weather, burn the settlement and kill off most of the pest infestations, rebuild and move back in before the weather turned harsh.
And the buildings in that period were fairly simple constructions so harvest wouldn’t much interfere with the process.
Could be, although it seems like it would happen more often, and would involve dismantling of a “sick” structure, the demolition then taken a safe distance out of town and incinerated. Also, could easily have been both ways — the comprehensive fires that took everything at once being the unplanned events.