Apple Music streams not combining with Spotify Streams

I recently began using Apple Music (mainly just to use the free trial to see if I liked it more than Spotify), and I noticed that certain songs that I streamed on Apple Music are not combining with the same songs I streamed on Spotify, but some are combining. An example is “Tempest” by Ethel Cain. I have over 1,000 streams via Spotify stats, but it is now beginning to count separately through Apple Music. Yet, same artist, “Ptolemaea” by Ethel Cain is combining streams together. So I’m just a bit confused, and I really don’t want the stream count to restart on my favorite songs that have high streams.