Likely, you've enabled an option on your camera to change the aspect ratio. A different ratio will use different dimentions and result in some cropping. These settings are then respected by Lightroom so that your precrop is applied.
I don't think that's the case as I'm shooting in RAW. With the RAW setting,
I don't have a choice of aspect ratio, only with jpeg.
At this point, this is a known issue with no known solution. Until a fix is found, I remove the crop in Lightroom on one photo, and then synchronize to the other photos.
OK, so if I go to Photo, Develop settings, copy; and then try to sync
thatwith other photos, the sync option is greyed out.
Is that the way I would do it?**
In the Develop Module go to the first photo and remove the crop using the Crop Tool (Keyboard shortcut - R).
Next, be sure that the first photo is still selected. Click on it in the film strip and confirm that the border is white.
Next, hold the shift key and click on the last photo in the film strip which will cause all of the photos to have a white border which is darker than the first photo which is the "most selected" photo.
Now the "Sync Settings" button will turn white and you can click it. In the Sync dialog click the Check None button.
Next place check marks in the Crop and Process Version boxes
Finally click Synchronize.
I suggest that you read Martin Evening's and/or Scott Kelby's book(s) on Lightroom 4.
If you have recently downloaded Fuji firmware, that's where the problem lies. I had the same problem when using Camera RAW with a Fuji X-E2 after downloading Fuji's latest firmware. My downloaded images all opened at a crop of 16:9, although my camera is set at at a full image crop of 3:2.
A temporary fix is to cancel the control for "average metering" by choosing either "multi" or "spot". Eventually, Fuji will solve this firmware problem, so stay tuned to their announcements.