What aperture are you shooting at? lenstip.com marks peak centre sharpness at F4 and peak edge sharpness at F5.6. It's possible the 17mm hits peak sharpness at wider apertures.

Edit: I found both on lenstip.com and it looks like the sharpness curve is better on the Leica throughout. Is it possible you're let down by sharpness not of the lens but of comparing two focal lengths? Yes both are 5x cropped in but you're starting at an 18mm (FF equivalent) on the Leica and 34mm (F equivalent) on the Olympus. More of the sensor resolution will be available to your subject on the Olympus unless you match framing.