No need to report this within Unity (unless I can invoice since I'm confident I wasted my time reporting this same bug ~5 years ago). Any Jr QA can repro this with ease: 1. Drag (or otherwise change) a Canvas GameObj 2. CTRL+Z (undo) 3. Poof! IT'S GONE?! Well, invisible. 4. CTRL+Y (redo) -> Nope, still invisible. 5. Workaround: CLOSE prefab or scene -> Reopen. The worst, if you're not ready to save. Since positioning or concepting requires a ton of CTRL+Z efforts, this happens way more often than it should (again, this bug has been around for years since ~5.4).