While we work out whether PlayTo is broken or not you could try to just set the position or progress directly. (I’m assuming you’re looking to seek to a specific point in the video?)
However, you should be aware that the video tag only implements coarse seeking so the granularity here depends on the keyframes in the video (e.g. you’re unlikely to hit the exact point in time / progress you’re requesting)
Setting video1.Progress worked great. I made video1.Progress observable and displayed it in a text field. That helped with figuring what values to use. The Video.Position property didn’t work.