Inaccurate damage display on spatial surge
What you see when looking at the damage display number is the cumulative damage since you first started using Spatial Surge without a different skill in between. For some reason the damage display doesn’t reset between individual Spatial Surge attacks when you’re auto-attacking and keeps adding up the damage of your first, second and third auto-attack … etc.
The same happens when using Flamethrower #1 … and probably every other channel auto-attack.
You don’t deal more damage. It’s a display bug that should be fixed.