Issues with hugo module dependency version resolution

I’m trying to go for a modular website. This is the project structure:

site (module)
  - theme (module)
    - bootstrap (module)
    - svg icon system (module)

Now, my svg-icon-system module depends on FontAwesome version 5.15.4 as is shown in the module’s go.mod.

When I do hugo mod graph in my theme folder, I get:

❯ hugo mod graph
github.com/UtkarshVerma/hugo-yoru github.com/UtkarshVerma/hugo-modules/bootstrap-v5@v0.0.0-20211227063022-65ec41aa3f2c
github.com/UtkarshVerma/hugo-modules/bootstrap-v5@v0.0.0-20211227063022-65ec41aa3f2c github.com/twbs/bootstrap@v5.1.3+incompatible
github.com/UtkarshVerma/hugo-modules/bootstrap-v5@v0.0.0-20211227063022-65ec41aa3f2c github.com/popperjs/popper-core@v2.10.2+incompatible+vendor
github.com/UtkarshVerma/hugo-yoru github.com/UtkarshVerma/hugo-modules/svg-icon-system@v0.0.0-20211227063022-65ec41aa3f2c
github.com/UtkarshVerma/hugo-modules/svg-icon-system@v0.0.0-20211227063022-65ec41aa3f2c github.com/FortAwesome/Font-Awesome@v0.0.0-20210804190922-7d3d774145ac

which is as expected.

However, when I do hugo mod graph in my website folder, I get:

go get: added github.com/UtkarshVerma/hugo-yoru v0.0.0-00010101000000-000000000000
hugo: downloading modules …
go get: added github.com/twbs/bootstrap v5.1.3+incompatible
go get: added github.com/FortAwesome/Font-Awesome v4.7.0+incompatible
hugo: collected modules in 6262 ms

I find this really weird. I don’t know how it is resolving the v4.7.0 even when the svg-icon-system module clearly depends on another version.

My website and theme are quite bare-bones, with the following configs:

#site/config.yaml
module:
  imports:
    - path: github.com/UtkarshVerma/hugo-yoru
// site/go.mod
module bitbanged.com

go 1.17

replace github.com/UtkarshVerma/hugo-yoru => ../hugo-yoru

require (
	github.com/FortAwesome/Font-Awesome v4.7.0+incompatible // indirect
	github.com/UtkarshVerma/hugo-yoru v0.0.0-00010101000000-000000000000 // indirect
	github.com/twbs/bootstrap v5.1.3+incompatible // indirect
)
#theme/config.yaml
module:
  imports:
    - path: github.com/UtkarshVerma/hugo-modules/bootstrap-v5
    - path: github.com/UtkarshVerma/hugo-modules/svg-icon-system