You are right - it's better described as a productivity issue. I turned on the game this morning and the 2nd hut was right where I left it - 60% completed. There was plenty of food in the bin. As soon as the game was 'on', all the villagers starting moving towards the hut, with the description 'building hut'. But they were 'assigned' there last night and were building away (under the direction of the chief) when I shut the game down.

I had more than 400 food when I shut down last night. They all 'appeared' to be near the 'removing rubble' area when I started this morning, yet no progress was made there, either. And very few tech points added overnight.