Undefined variable false negative

[arndeash]

I love blendid so far, but for some reason I get these false negatives when using variables, see error message bellow or screenshot (https://cl.ly/3C0U1I1s3l1B)

[15:11:06] gulp-notify: [Error running Gulp] Error in plugin 'gulp-sass'
Message:
    ../../src/stylesheets/custom/style.scss
Error:
Undefined variable:
"$font-size-sm".
        on line 2 of ../../src/stylesheets/custom/style.scss
>>   font-size:
$font-size-sm;
   -------------^
Details:
    status:
1
    file:
/Users/andreas/Coding/mittanbud/emg-styleguide/src/stylesheets/custom/style.scss
    line:
2
    column:
14
    formatted:

My directory structure is like this:

/stylesheets/bootstrap
/stylesheets/custom/custom_variables.scss
/stylesheets/custom/style.scss
/stylesheets/app.scss

and my app.scss looks like this:

@import "custom/custom_variables";
@import "bootstrap/bootstrap"; 
@import "custom/style";