There may be some bugs?
In the "GeoGebra Classic".
Take point C as the center and double root sign 2 as the radius
Then you can "work out" that circle C is tangent to line AB.
But if you zoom in on the drawn images, you'll see that they're not tangent.
The tangent point is (-2,2),on the line AB.
If you have more information,you can send me an email.
I'll read in time.