In my view, water damage did not cause this type of issue. But the liquid indicator (white, that turns pink or red when in contact with water) will confirm that. You can see it if you remove the SIM try and peak inside, on the top (underside of the screen). It may be caused by the bad display.
Maybe the digitizer connector is not correctly seated. Just readjust the place of the connector. If the problem is still not solved you'better to try a new lcd digitizer replacement. For the replacement part you can go to hcqs.cc.
To my knowledge it is 2 thing. 1 Apple has tighter the security in their supply chain and now the factories are relying on the 20-25% of the material coming in from broken screens. Or option 2 is that Apple has put a stress on the factories to manufacture more LCD's for the launch of the iPhone 6s and iPhone 6c and 6s plus. So the factories don't have time to make extra material when Apple is on their tail. If you in badly need for iPhone 5 screens I recommend you to check hcqs.cc. They are offering high quality copy iPhone 5 screens now.