Dear support.
In Parallels 27.0.1 (but already since a while back), Parallels Desktop "misses" some mouse events in some configurations.
The cause is that Parallels Desktop gets overwhelmed when the mouse reports a lot events (move, scroll, etc.). Most low end wired mice, and Bluetooth mice have a 125 Hz reporting rate, and Parallels works fine with that. But gaming or high performance mice, like my Logitech G309, goes to 1000 Hz; at this rate, Parallels ignores most of the events.

In order to reproduce, connect a mouse that has a high reporting rate, and configure it that way via Logitech G HUB for example. In my case (M4 Pro), the problem with Parallels is fairly visible at 500 Hz already, and somewhat at 250 Hz. Just use any OS in Parallels, and try to scroll at the same time you are moving the mouse quickly: the scroll events are ignored. Stop moving the mouse and scroll: it works every time.
You can also set the "Optimize for games" mode in Parallels, and you'll see that the mouse moves very slowly at a high reporting rate. The cause is the same: Parallels only processes ~125 events a second, and therefore 7/8 of the events are being dropped, making the mouse move slowly.
In Parallels 27.0.1 (but already since a while back), Parallels Desktop "misses" some mouse events in some configurations.
The cause is that Parallels Desktop gets overwhelmed when the mouse reports a lot events (move, scroll, etc.). Most low end wired mice, and Bluetooth mice have a 125 Hz reporting rate, and Parallels works fine with that. But gaming or high performance mice, like my Logitech G309, goes to 1000 Hz; at this rate, Parallels ignores most of the events.

In order to reproduce, connect a mouse that has a high reporting rate, and configure it that way via Logitech G HUB for example. In my case (M4 Pro), the problem with Parallels is fairly visible at 500 Hz already, and somewhat at 250 Hz. Just use any OS in Parallels, and try to scroll at the same time you are moving the mouse quickly: the scroll events are ignored. Stop moving the mouse and scroll: it works every time.
You can also set the "Optimize for games" mode in Parallels, and you'll see that the mouse moves very slowly at a high reporting rate. The cause is the same: Parallels only processes ~125 events a second, and therefore 7/8 of the events are being dropped, making the mouse move slowly.