It is a testpoint symbol.
For some reason the pad is marked as a testpoint.
You can set this by first select the pad. RMB > Properties.
In the Pin Properties dialog there is a 'Test point' checbox you can enable/disable.
Another way is just to hide the symbols.
This can be done in 'Tools > Options > Routing > General'
In this dialog you can enable/disable the 'Show test points' checkbox.