Lightroom - RAW file - How to fully view image

If you are using Classic there is a plugin from Adobe labs called DNG recover edges that you can use to recover the cropped areas that will sometimes work for these. Unfortunately Adobe made the decision to implement these in-camera crops by throwing away the data. Lots of people complain about this. They do the same thing with automatic lens corrections for mirrorless cameras that can't be turned off. It's very unfortunate that there is no way to turn either of those off and you lose parts of the data. Many threads on https://feedback.photoshop.com on this such as https://feedback.photoshop.com/photoshop_family/topics/disable-built-in-lens-profile . The feedback site is where Adobe takes feature requests and bug reports. The current forum is for users to help each other out and there are no real Adobe engineers here.

Quite possibly you have set an in-camera crop ratio, e.g. 4x3 on a camera which natively shoots 3x2. In Lightroom try opening the crop tool to see if the additional data is there, in which which you should be able to recover it by resetting the crop.