I figured out a solution. Apparently this is being caused by an inability to completely clear the old camera raw edits from the DNG files. In Bridge, I did both "clear settings" and reset the image to "camera raw defaults" but there was still some part of the old raw edits being retained.
breakout game (https://breakoutgame.io)
I went back and simply re-created the DNG sequence anew from the original raw file with the pyraw2dng script. With fresh dng files, Camera Raw 11.3 worked normally.
To diagnose the issue, add a spot healing instance to Photoshop CC Camera Raw. When you open the image in Photoshop or preview it in Bridge, the rectangular box artifact will appear.