Backport PR #37613 on branch 1.1.x: BUG: read-only values in cython funcs
Backport PR #37613

will update milestones on PR and associated issues once this is green-ish. Will also need to update release notes on master. (move from 1.2 to 1.1.5)
@simonjayhawkins whats your preferred way to move forward here? i would prob just close this backport (and fix the release note), but either way ok any resolution on this one (happy to just not backport as well). leave it open, I keep putting this off!, but the open issues on 1.1.5 milestone is getting less, so can't put it off much longer! closing for now. nothing needs to change on master as milestone and release note are 1.2 for #37613