An Unusual Issue Slowing Down Lightroom Classic (And How I Fixed It)

I had taken some photos over the weekend, and I was processing them in Lightroom when I noticed that the software was acting unusually. When I applied a preset, the preview worked perfectly, but it took a few seconds to actually apply. At first I thought that maybe this was an issue with the new version of Lightroom, so I quit and restarted. It was then that I noticed another weird issue: the software was still trying to write the metadata to disk. So I thought that maybe my disk was running out of space. I checked, and there was still lots of room. Curiouser and curiouser I thought. While it turned out not to be a disk space issue, I was actually close to the source of the problem, thinking it was disk-related.