1. Open map
2. Enable Turret Coverage
3. Zoom in to the point where you would get World View if you had a radar coverage in that area
4. Keep zooming in, at every step the artillery coverage will look different
This happens both when holding a remote and when having a hand empty. This bug exists for a while, I haven't noticed whether it was introduced in a specific release or whether it was there always.
Why it matters? When using artillery to discover distant part of the maps I go over the edge very carefully to discover the furthest chunk possible. By shooting close to the edge it is possible to discover chunks which are out of range of artillery.