This is my first time reporting a bug in this forum.
On my second horde night (day 14), I was fighting on an elevated horde base 5 blocks high (all cobblestone). I then randomly fell through my base onto the ground (asphalt) at around 0200H, and was eaten by zombies.
On another horde night (day 49 or 56), I placed a sledge turret on top of my horde base to fight off birds. However in the morning I found my sledge turret inside the base. The base is made of reinforced steel blocks.