What causes iTunes to lose track of songs on Mac?

Every time I sync my music to my phone, there is one song iTunes "cannot find" - when I search in Finder I see several copies of it (live, remix, etc). The thing is, I can't tell where iTunes thinks it's missing from. Something is looking for a file that it can't find, but I don't know if it's a playlist or album or what. How do I find which link is broken?

I'm using iPhone 13Pro (updated iOS) and MacBook Air Sequoia 15.5 (24F74)

[Re-Titled by Moderator]

Original Title: ONE missing song of multiple copies