[Prusa i3] Too much extrusion, only on edges

[printbus]

... I think i may be printing support material too fast, what do you think?

Hard to say. You haven't shared your support settings. We don't know what you have for a hot end. We don't know what you have for an extruder scheme. We don't have a link to a specific product page where we could figure out what you have there for a printer.

For me, extrusion stopping has typically been from being too aggressive with retraction settings. I have a hobbed bolt extruder scheme, and aggressive retraction can cause the same area of filament to roll back and forth on the knife edges of the hobbed bolt, simply causing the filament to be carved away...