I am using Maaslin2 to analyze the association of pathway abundance (copies per million) and sample metadata using a negative binomial model. I recently added some additional variables to my metadata table and re-ran Maaslin2. I compared the significant results from my first Maaslin2 run to those generated in my second Maaslin2 run, and noticed that by adding more metadata variables the number of significant features changed. Additionally, some metadata variables that previously had significant features no longer do. Is this specific to the model I’m choosing to use or to how Maaslin2 works?