I'm not sure what you are reporting.
- If you just don't want the staircase, the GSX parking customization page has a specific option "Disable staircases"
- If, instead, you are reporting the wrong staircase type, that's a problem of the configuration of your airplane. The rear door is probably not set correctly. If you are using a custom configuration for that airplane, try to Reset it, so GSX will use its own internal configuration instead of the one you made.