I've got 387 graves, but only 70 burial spots. After I sold all my graves and rebought them, it went back to having the same number of graves and burial spots.
The changelog said that bodies should rot over time, but I think bodies rotting is reducing the number of total burial spots instead of the number of filled burial spots.
Another bug: sick people reduce health, and low health causes people to get sick. At a high population, this causes an endless loop where my health gets stuck at around 5% even with all the other health bonuses.