There are quite many given that I only started using Sequoia a few weeks ago, and all happen only on Sequoia, not on my other macOS versions. A nasty one I discovered last week is e.g. that I have to delete and re-add an application (which generates key events for the operating system) to Privacy/Accessibility each time I re-compile it, otherwise the events are simply swallowed without any error. If you happen to be an Apple representative, we can continue by email.