A cap front curves away in two directions, has a stiff seam running up the middle and only gets held by the frame across part of the panel. Hats bring their own problems: a bucket hat has a soft, narrow crown panel, and a broad-brim hat often has a firm brim close to the design.
Run a flat-garment file on a cap and the design drifts. Stitching from one side to the other pushes the fabric ahead of the needle, so by the time the machine reaches the far edge the outline no longer meets the fill and the logo sits off-centre on the head.
That is why cap files are sequenced from the centre outwards and laid out so lettering never has to cross the seam ridge. If the same logo also goes on polos or work shirts, it needs its own flat file: see logo digitising for flat garments or left chest sizing.
If your caps keep coming out crooked, off-centre or with a gap down the middle that never shows on polos, you are almost certainly running a flat-garment file on a cap frame. That is a digitising problem, not an operator one.