We're having weird issues with the Windows setup under CI failing. Somehow the R setup action installs R 4.5, but then installation of nimble uses R 4.4, and there is some issue with loading the rlang dll, so the nimble install fails and testing can't be done.
I monkeyed around but wasn't able to fix this other than by setting the R version under Windows to be 4.4.
Posting this for future reference and as a reminder that at some point we'll need to try a current R version under Windows to see if the problem has resolved itself.