Running "sync" fixed it:
[root@lenovo-pc ~]# sync [root@lenovo-pc ~]# debugfs debugfs 1.44.6 (5-Mar-2019) debugfs: open /dev/mapper/fedora-root debugfs: icheck 345053591 Block Inode number 345053591 86246540 debugfs: quit [root@lenovo-pc ~]#
The "find" command identified it as an old file in my home directory that hasn't changed in 11 years. I have everything backed up on the other machine, so copied the file back from there. After doing that, the "Current Pending Sector Count" went from 1 to 0. The "Uncorrectable Sector Count" is still 1. A short smartctl test was successful.