I am also observing this on Windows with Emacs 28. Reverting to Emacs 27.2
resolved the issue.

I was also able to work around this issue on Emacs 28 by using an
around-advice similar to the one provided by Faerryn but tailored for
straight.el, wrapping function straight--build-autoloads.

You can find other users running into this problem in this straight.el
issue: https://github.com/raxod502/straight.el/issues/701