Ok I can't edit my post, so I have to do a new post to update my "plight".
My villagers have now re-completed all the constructable structures except clearing the blockage, restoring the garden and move the boulder.
These three puzzles appeared solved in the Puzzle status. However, they are all unsolved in the game itself. The 1st time my puzzles became unsolved, I was not able to move the boulder ever again because the status said it has been solved.
This time my puzzles became unsolved again, my lagoon and garden became two unsolvable puzzles because they're also considered solved by the puzzle status.
If I pull the villagers over the site of the blockage, they are confused and said more researched may be needed. But they will automatically go clear the blockage by themselves and then they are not confused by it. But it can't never be solved because the foundation is never built. So they just kept clearing the blockage to no end.
They are also curious about the field (where the garden is supposed to be restored) when I pull them there or they get curious on their own. But if I bring a nursing mom over, she feels very good in the garden?!
I have screenshots if you need them and also the savegame.pdb for yesterday's game and the last one before the game went haywired again for the 2nd time.