High activity scores does not mean high expression level?

[Sirin24]

Hi, I ran pyscenic on a loom file that contains diseased and healthy cells (2 conditions) and I plotted a heatmap of the auc scores and it seems whenever i find a TF with different activity, the expression levels is the same in the 2 conditions or even the opposite to the activity! Does this mean that high activity scores does not mean high expression level?

Another question I have i plotted a umap/tsne and it seems that the regulons separated the celltypes well but the diseased and healthy are in the same clusters. I am not sure what I am supposed to find when doing the umap.