I have not heard of this particular problem with the X-H1 before. I am not saying it doesn't exist, I just am not aware of it. I do not own the XF 16 - 80 lens, however I did perform a test with the XF 10 - 24, XF 16 - 55 and XF 100 - 400 all mounted on my X-H1. All at low shutter speeds of about 1/25. All were shot at focal lengths of 24mm, 55mm and 400mm respectively and I saw no difference in sharpness whether the IS was set to continuous or shooting only. All images were very sharp. You might want to contact Fuji.