Pathway analysis always generating impact of 1 for a specific pathway

Hello all!

For my data I am getting a pathway impact of 1 for the aromatic (phenylalanine, tryptophan, tyrosine) amino acid biosynthesis pathway for all of my sample comparisons. Is this most likely a result of the metabolites that were included within the document? I would think even though all of the comparisons have the same metabolites that there might be at least some difference in terms of the impact, as seen with all of the other pathways that are shown.

Thanks in advance for any insight!