Unfortunately that happens on some claims. I know that the claim markers on Eagle Eye have been put up then removed by non members in the past. If you have your printed GPAA Mining Guide and use the Center of Claim from the GPAA Online Mining Guide you will see that working in Estes Creek from the center point to the NE or to the SW gives you years of claim to work without getting outside of the west or east boundaries.
You can also create a 3D map in Google that you can print and drop location pins where every you would like. Follow this link for a tutorial. https://www.youtube.com/watch?v=LZB4qX8r2xk
Hope this helps.