As far as I’m aware, this is a Repetier-Host-only problem. If you just send the file to Marlin, it will plot/carve correctly even though the display in Repetier-Host is crazy. Turning off arc commands in EstlCAM (or whatever CAM tool you are using) “fixes” the problem because Repetier-Host no has to plot arcs. Alternately you can downgrade to version 2.1.6 of Repetier-Host.
The setting in EstlCAM (as highlighted by Aaron) is under Setup/CNC Programs. You want to uncheck this:
