Placing landfill anywhere (even far from the character) results in more landfill appearing near the character when he is standing exactly on the border between water and land.

Example:
Before placing landfill:
20200424223619_1.jpg

After placing landfill:
20200424223622_1.jpg

Extra notes ...

I experienced the same problem in the first connection attempt; however, the game worked fine for me in the second attempt.

I have both dump and log files of the first attempt, hope it helps!