It sounds like she is really confused and might do well with a change in training plan.
You could see if using a puppy play pen and a doggy litterbox will work for her. You could even use a covered cat box to hold the dog litter. Once she is using it regularly you could move it closer to the door and then outside to get her used to going outside and slowly remove the box once she has the idea that she can go outside to go.
You can read here about doggy litterbox training
and see a puppy play pen type enclosure here
there are several different types available and local pet supply stores should carry some.
What has happened is she is habituated to using the enclosed space for pottying. She may need the plastic wall visual to manage to go or the door grate view. Because she thinks that is the right place to go she waits to get there to potty. Its a shame her breeder accidentally taught her that but to get past it you may have to work within what she sees as the 'rules' for where dogs can go to slowly get her outside and used to something different.
Hope this helps you!
Yes exactly and then if you want her outdoor trained slowly move the box outside, or put a second box outside for her to use.
You can use the outdoor box to get her outside to potty and slowly change to there being say a 'box' with no bottom so she is going on the ground.
She just has it in her head she needs to use the 'box' so the idea will be to outfox her so she thinks she is doing it right the same as always while you work at her doing it the way you prefer.