Walking through walls and X-Raying exploit

Attempting a connection to a Realm and cancelling before fully connecting, then joining an offline singleplayer world seems to produce a variety of effects, the most notable and dangerous of which seems to be that the Realm world is loaded into the offline one, but using the offline world's block hitboxes. This can potentially mean that with a specific superflat world setup, for example, players would be capable to simply walk around through walls and be capable of finding valuables, mineshafts, strongholds, etc. at little effort or expense. Attempting to save and quit the world at this point, however, softlocks the game and needs to be forcibly closed. It's consistent to perform if you can get it within a few attempts, although may require a few restarts to be able to pull off, as it seems that if one doesn't pull it off the first few times, they likely can't perform it without a game restart or two.

 

Visual demonstration and example: https://youtu.be/QLZ-3Ffjiag