My phone randomly chimes but there is no notification for it!

For the past couple of weeks, my phone has randomly begun chiming. It sounds like soft bells but when I check my notification there is nothing new that could possibly correlate with the chime. It’s like a 5 second song that plays. It happens randomly throughout the day. (Maybe once or twice) and then there are days where it won’t chime at all. I have an iPhone 12. I’ve check all my notifications on the settings menu. But haven’t found any app that the banner has been turned off. It’s not annoying or anything but it is a little creepy. I