Scooping a measuring cup straight into a bag can compact the flour. The cup still looks full in the expected way, but it may hold more flour than the recipe intended.
Use the recipe's weight measurement when available. Put the bowl on a kitchen scale, zero it, and add the flour. If working with cups, follow the author's measuring method rather than assuming every cupful is identical.
This matters particularly in small batches, where a modest error becomes a larger share of the total. Dry cookies or a stiff batter may reflect measurement rather than a problem with vegan baking itself.
Keep different flours clearly labeled. A weight of bread flour, wholemeal flour, and a gluten-free blend does not guarantee the same absorption or structure. The scale helps you measure accurately; it does not make the ingredients interchangeable.