Auto transmission jumps in reverse only
 

I have owned my 323 Protoge since new (1999 1.8l auto model).
The auto transmission appears to work perfectly with any forward 'gear' selected.
In reverse and on an incline if I depress the throttle too fast and/or far the transmission appears to disengage for a split second and then re-engage with a resulting jolt.
This does not happen with a light throttle.
Any ideas?