I am running into an issue with the latest 2 beta drops of 18 when using Stage Manager with an external monitor. I have the ipad directly below the monitor and when I move the mouse to the other screen it shifts dramatically right then go to the proper position about an inch up the screen. This issue can easily be duplicated. I can share a video if I am given the proper way to do so. This worked fine with the first beta release. Please contact me because it will cause issues when the gold release is dropped. I have found smaller bugs but this is bad.
You should probably raise this as a bug in the usual way. It won't really get progressed if it's only posted in these Developer Forums.
You need to raise each issue you find separately at https://feedbackassistant.apple.com/ You can post the FB numbers here if you want, so that others can link to them.