I, too, am having similar issues. However, depending upon yet-to-be-determined conditions, the problem has manifested itself in both X & Y directions, as well as in the Z axis. I have not tried to lower the belt tension, but it is probably a good idea. It goes along with my impression that the problem is that the motors cannot handle the sudden movement requested (I use slic3r), and that movement in one direction (for instance in the negative X, Y, or Z axes) is being hampered.
In my case, my carriage kept moving up away from the bed, until I realized that my double motors had become maligned, and the print carriage was no longer perpendicular to the two vertical screws. Realigning the horizontal carriage solved my Z problem, so it turned out to not be an issue with the firmware (I, too, had upgraded to 2.0.5.x).
However, I am still trying to determine the cause for the X and Y behavior. My prints keep moving across the bed because the motors are not moving the print head back towards the zero position.
In my case, my carriage kept moving up away from the bed, until I realized that my double motors had become maligned, and the print carriage was no longer perpendicular to the two vertical screws. Realigning the horizontal carriage solved my Z problem, so it turned out to not be an issue with the firmware (I, too, had upgraded to 2.0.5.x).
However, I am still trying to determine the cause for the X and Y behavior. My prints keep moving across the bed because the motors are not moving the print head back towards the zero position.