Org-publish error with „called org-fold-core-region with missing SPEC”

If you call org-set-property as part of your org-publish-all functions and you use latest version of org-mode you might encountered the called 'org-fold-core-region' with missing SPEC error.

To workaround it, just set org-fold-core-style to its pre org-mode 9.6 default value (it changed with 9.6), like this:

(setq org-fold-core-style  'overlay)

Not a fix, just a workaround but it makes org-publish-all happy, so happy hacking!