Music Not Showing Newly Impoted Songs When Moved To A New iMac

I had iTunes on an Old iMac (let's call it iMac1). I started using Music on a new iMac (let's call it iMac2) and pointed Music to the .itl file on iMac2 so it could import my songs. I then added some new songs to iMac2 over the next few days. All of this worked fine. Today I got another new iMac (let's call it iMac3) and Music on this one again points to the .itl file; however, imported library on iMac3 contains songs that were on iMac1, but no additions made when using iMac2. I looked in the individual folders of my library on iMac3 and all the songs are there, just not importing. What's going on?