I have exactly the same problem with my X-T1 and 16-55mm and 18-135 as well. And others have too :-(( Seek in forums..- for instance: https://www.dpreview.com/forums/thread/3864634
Shortly: on tripod, aperture 5.6-8, landscape shooting(distant objects), autofocus-"small zone". Priority is focusing - not release!! Each time you receive focus confirmation - green led.
From 20-25 shots you have about 30% blurred photos. Very sad. Not happens with prime lens - 16mm or 23mm. The only way to correct it is to do doubled shots.