Sadly, changing scope order or even removal of first one (layout: "post") does not resolve the issue. The home layout is only applied to root URL (localhost:4000/), but not to other index.md in sub URL (ex., localhost:4000/docs/)
I used collection name “pages”, so my posts are located as follow:
_pages/index.md <-- home layout
_pages/docs1/index.md <-- home layout
_pages/docs1/postA.md <-- post layout
_pages/docs2/index.md <-- home layout
_pages/docs2/postB.md <-- post layout
_pages/docs2/postC.md <-- post layout
...
It works only for files within a given folder or files with specific names in any folder. Files ending with specific words require regex but Jekyll doesn’t seem to support Regex in scope path.
A plugin does seem to provide this functionality, but it also no longer maintained.