Fine, I have measured Input 1 as well. UR-22 has hybrid input connectors which means you can plug either an XLR or a 6.3 mm jack into them. No phantom power is present on any of the jack inputs, regardless of the state of the phantom power switch or the high-impedance button. So it is safe to use a guitar while phantom power is on if you connect it via jack.
What still bugs me a little bit is that it has its phantom power switch is on the back panel while the user manual tells me to keep it off when I don’t use an input device that requires it. It’s pretty inconvenient to reach at the back of the unit and then find the switch. On the front panel there would have been enough room to place it there, for example at the bottom-right corner where there is a steinberg logo now. I don’t see the logic why the phantom switch had to go to the back. Although this is “fixed” on UR-44, not everyone needs four inputs who would need a convenient phantom power switch. 