IIRC, I was just manually checking stable versions on godbolt.org in that issue.
Edit: Actually, looking back at the issue, I do talk about nightlies there after all.... anyways, checking whether the stable versions behave the same is probably sufficient information to form a good guess whether or not it's "the same" issue.
Edit2: You can also install the nightlies mentioned in the issue manually and just check whether or not behavior changes in the same way at the same points.
Edit3: Regarding cargo-bisect-rustc, I don't know what you mean by "walks nightly-by-nightly", maybe you didn't pass it a start point and end point?