If you're getting unexpected results with the metronome, it's likely because the app is not in the foreground. To prevent that, make sure Upbeat is in a Chrome window by itself, without other tabs on that window. If you need multiple browser tabs open at the same time, put the other tabs in a separate window, not the one running Upbeat. This will allow Google Chrome to prioritize Upbeat, instead of treating it as a background "unused" tab.