Extremely loud screeching noise on my iphoneX and ipad

I experienced a loud, screeching noise coming from my iphoneX and ipad in the middle of the night when neither one was in use. The sound was similar to a smoke alarm. This sound first came from my iphone, i powered down the phone, then waited a few minutes and powered it up. Ten minutes later the same screeching noise was coming from my ipad. I powered down both devises until the morning when I could search the internet for a solution to this problem. I found many people with similar experiences, dating back to the iphone 6, but no answers. FYI - I recently updated the software on both devised to iOS 14.6.

This noise could seriously damage the users hearing if they were using earbuds. Does anyone have an idea on how to fix this problem, or if it is being addressed.