Problem when rotation

When i am converting S3 Pro Raw file using C1 PRO 3.71 , while i rorate the image by typing the value , i.e. 90 in the rotation button but not using that one in pull down menu, my output jpeg image is cropped ! for example when it is 500 x 752 the finally image will become 500 x 6xx~ the result is not just few pixel but a quite a large portion . I am sure i haven't use any crop tools!! and the preview is also state that output is 500 X 752 !! Anybody can answer this Qs? thx !