Well, I tried to recreate it with your sample but was unsuccessful. In my app I inherit the circular gauge into my own class and add additional properties and methods. I use the Major/Minor TickSettings Length and Offset properties which cause the elongated tick marks. When I switch over to the StartOffset and EndOffset properties, it works fine. Since I was unable to mimic the behavior using the Length and Offset properties in your sample app, I can only conclude that it has something to do the the inheritance in Android (iOS and Windows 10 are good).
Your sample app actually helped me understand the StartOffset and EndOffset properties and since my app allows the user to resize the gauge, these properties were much better suited for that task than the Length and Offset properties. So I have converted my app over and no longer using the Length and Offset properties so this issue is resolved for me.
On a down day when it's raining and not snowing in our mountains, I will attempt again to recreate the scenario using an inherited class in your sample to see if I can help you figure out what is going on (unless you beat me to it).
Thanks for the help.