What sites are people visiting? I've used Firefox for over a decade and yet have to run into any kind of issue like this.
16 karma · joined August 13, 2020
You use the 12-hour AM/PM representation in the "I have to wake up at..." picker and in your text below that.
But the actual calculated bed time uses the (imo better) 24-hour format. This could lead to confusion, but at least is somewhat inconsistent.