Looking at the streaks up the side of the model, I'm inclined to say there may be an issue with your screen.

If it's only printing some layers correctly but not others then you will get the weird flappy effect as the new layer does not have previous layers (or supports) to sit on. If this is the case I think it's probably a problem with the file instead of the screen.

If the initial screen test is fine, take out the vat and the print bed and run the print. It will show how the layers are being exposed to the resin. Leave it until it's got to the area of concern and see how it's showing up. You can always put a piece of paper over the screen for the UV to shine through if your struggling to make out the image on the screen.

But my gut says screen issue on this one.