I’ve noticed that when a hash fragment is present, DOM.uid doesn’t work correctly. You can see an example here (#foo causes clipping to revert to its broken state) : https://observablehq.com/@mbostock/svg-clipping-test#foo
I submitted a PR here to fix it by just trimming off the existing hash fragment before adding a new one. I thought perhaps it got lost in the shuffle so that it would be appropriate to report it more directly here. Thanks!