Ok...i had a look at the app that you sent to me...it's looks really strange. The edges of some polygons are transparent in some cases. You simply see the camera image shining through. I managed to bring the door in a position where actually the whole thing was more or less transparent.
Then, i fired up my test case and tried to reproduce it...i failed...until i enabled AA more or less by accident and then, i got the same visual artifacts in my test app. So i assume, that the issue will disappear if you disable AA. If that's the case, then i've no idea what i can do against this. Most likely nothing, because the AA implementation is part of the GPU hardware. And if it thinks that this is the right way to do it, then i can't tell it otherwise. I fiddled around with the EGL-config settings for AA, but to no avail...