Error expanding "": permalink ill-formed

when trying to configure permalinks on my site, I keep getting the error
“ERROR failed to create resource spec: error expanding “”: permalink ill-formed”

I’ve tried all sorts of combinations, even copied the complete example in content-management/urls/#permalinks-monolingual-examples - same error.

if I do it like here: (sorry, wasnt allowed to post full link)
there is no error, but only the urls of pages are altered.

produced the error.

I am unable to build your site.

File to import not found or unreadable: hugo/node_modules/bootstrap/scss/functions

I’ve created another example on a site that doesn’t require node modules:

The ability to define permalinks for different page kinds was introduced in v0.115.0.

Check your local and production versions; they all need to be v0.115.0 or later.

Also, if you do this…

foo = '/'

the home page and section page are rendered to the same path, one clobbering the other.