The escape key in the bookmark dialog window now saves changes, just like <Enter>.
It should leave saved data unmodified.
This issue replaces another strange issue, which made me lose bookmarks and is reported here:
Brave Version 1.31.88 Chromium: 95.0.4638.69 (Official Build) (64-bit)
I’ll take a closer look at this later, but the original bug, and the fix, were from upstream Chromium; it’s very likely that an issue here would be as well and should probably get reported into the Chromium bug tracker.