I'm going to leave this open for now. If we want to put out a bugfix release for deep-diff1 we'd have to start by fixing the CI setup, and bringing our lambdaisland toolchain setup up to date (see bin/proj and bb.edn).

deep-diff2 has been out for a few years, and upgrading should be very straightforward, so unless someone comes around who is running into this issue and for some reason is unable to upgrade, I don't think there's enough reason to put effort into this.

To clarify for people coming across this issue. The aforementioned bug has been fixed in deep-diff2, this PR is specifically for the old deep-diff(1). We could release a new version of deep-diff1 with the fix, but there's some effort involved, and no one might really need it, so we're punting on this until someone steps up and explains why they need this.