Error calling partials when rendering page

[izikeros]

When generating the page I'm getting the error:

ERROR 2022/11/23 08:42:04 render of "page" failed: "/web/themes/hugo-w3-simple/layouts/_default/baseof.html:6:5": execute of template failed: template: _default/single.html:6:5: executing "_default/single.html" at <partial "head.html" .>: error calling partial: "/web/themes/hugo-w3-simple/layouts/partials/head.html:19:8": execute of template failed: template: partials/head.html:19:8: executing "partials/head.html" at <$.Scratch.Add>: error calling Add: can't apply the operator to the values

and more, similar errors for rendering "taxonomy", "section", "page"

I'm using:

$ hugo version
hugo v0.105.0+extended darwin/amd64 BuildDate=unknown

on macOS.

The page renders with e.g. 'ananke' theme.