Error in package--load-files-for-activation: (void-variable zenburn-fg+2)

[artforlife]

When updating to the latest Zenburn, I get the following error. If that matters, I am using auto-package-update, but I have seen this error when updating solely Zenburn as well. The theme does not load with this error.

Scraping files for zenburn-theme-autoloads.el... 
Generating autoloads for zenburn-theme.el...done
  INFO     Scraping files for zenburn-theme-autoloads.el...done
Wrote /home/user/.emacs.d/elpa/zenburn-theme-20220710.623/zenburn-theme-autoloads.el [2 times]
Error in package--load-files-for-activation: (void-variable zenburn-fg+2)
Checking /home/user/.emacs.d/elpa/zenburn-theme-20220710.623... [4 times]
Done (Total of 0 files compiled, 3 skipped)
Error in package--load-files-for-activation: (void-variable zenburn-fg+2)