So.. in the Precision Training deck, the "Find the Weakness" card gives an automatic Pierce 1 whenever an "Imperial Figure is attacking"

Does it mean only Imperial figures (a.k.a. non-scums) or is it for all units controlled by the Imperial player?

I believe the distinction was, if it says "Imperial", then it meany all units controlled... However, if it uses the symbol for the faction unit, then it means just specifically those faction units, even if they are included in a different faction's army./

Awesome. Thanks!

See "Imperial Figures" from the Rules Reference Guide.

During the campaign all figures controlled by the imperial player are imperial figures.

If an ability uses the affiliation symbol, then it refers to that affiliation only.