I tested with your Ubuntu version too. And to me there is memory leak.
Now I was testing to reduce the project complexity to identify where is the problem. And I see some curious happening.
The demo project was running all day long and increasing memory consumption. It takes hours to increase from from 102 KB to 106 KB. Then in just one moment it drops from 106 KB back to 102 KB.
It seems to be a Mono error?
Any one else has tested this project to see if there is a memory leak?