Can power frequency variation affect iPhone screen?

Question

Here is one for the electrical boffins. Earlier this week I travelled by French high-speed train (TGV) from Paris to Augsburg in Germany and returned a few days later. On the German section of the line I noticed erratic behaviour of my iPhone 5. The scrolling became jerky and the touch accuracy unpredictable. I tried sending an email several times and every time it got sent before I had finished typing, presumably because of random activation of the SEND button. My first thought, on the outward journey, was that the phone had developed a fault. I rebooted the device but found the same problem persisting.
I then had the idea of unplugging the Apple 5v euro charger from the train's 220v socket and was amazed to find the erratic behaviour completely cured. On the return journey to Paris I noticed the same phenomenon, but only on the German section of the six-hour journey. Since on both journeys I was seated on the top deck of the train, it did occur to me that I could be receiving interference from the the catenary which would have been just a few feet above my head. However, the more likely explanation is a a discrepancy in the frequency of the power supply.
The question is, can an incorrect frequency cause this sort of erratic behaviour in scrolling and touch?
For background, I did some checking on the power supplies on both sides of the Franco-German border. There is difference between the catenary power supply in Germany and France. In Germany, catenary is 15,000 volts with  frequency of 16-2/3Hz.  In France the supply is 25,000v at 50Hz. The train power generally is stepped down to 440v and then the lighting and individual power socket circuits are further stepped down to 220v AC at 50Hz (50Hz is the domestic frequency in both countries). Since the erratic behaviour was noticed only in Germany, there is possibly an explanation lurking here.
Does anyone have any ideas?

Answer 1

Go to Settings > General > Accessibility > Zoom and make sure it is OFF.
Zoom on has some strange interaction with the screen staying on with incoming calls. Not sure if it could account for your problem or not.
Phil