syna: Error building site with v0.17.3

Is this a BUG REPORT or FEATURE REQUEST?: bug

What happened:

With update of my webpage to Syna v0.17.3, the following error started to occur while running hugo server:

Building sites … WARN 2020/07/26 19:34:36 .File.Dir on zero object. Wrap it in if or with: {{ with     .File }}{{ .Dir }}{{ end }}
Built in 449 ms
Error: Error building site: POSTCSS: failed to transform "style.css" (text/css): resource "scss/styles/index.scss_02bf14281ac065540fcc7ecc15ca70a4" not found in file cache

BTW the same happens also on your okkur / syna-start project.

What you expected to happen:

No error occurs.

How to reproduce it (as minimally and precisely as possible):

1. Checkout syna-start with

git clone --recurse-submodules https://git.okkur.org/syna-start

1. Run hugo server.

Anything else we need to know?:

Environment:

• Syna Theme version: v0.17.3
• Hugo version: Hugo Static Site Generator v0.74.3/extended windows/amd64 BuildDate: unknown
• Others: OS Windows 10 Pro 64-bit