SASS Partials not compiling on some changes

Apologies if this is a redundant, I couldn't find anything similar enough to help my issue...

I'm running Gulp 4 on a Mac (OSX 10.12.6). Node 10.15.3 NPM 6.4.1 Gulp-SASS 4.0.2

When I make a change on a partial (whether in the main, or sub-directory) if the character count of the document remains the same, Gulp is run from the watch task, but the new CSS output doesn't compile.

Ex. If I change font-size: 9px to 10px, it compiles If I change font-size: 9px to 8px, it does not compile (even though Gulp runs the task) If I save a handful of changes that are the same length, it does not compile. If I then make a change that changes the character difference of the document by one character and save, it does compile.

Standard (non-partial) scss files do not seem to exhibit the behavior. When saved, the output file will then pick up any non-compiled changes from the partials.

Again, apologies if this is some confusion on my part in the setup, or if it's a redundant issue. Please let me know if I can provide any additional details or better examples. Thank you.

gulpfile.js:

'use strict';
// Requirements
const gulp         = require('gulp'),
      sass         = require('gulp-sass'),
      outputDir    = 'builds/dev/';

// Source Locations
var paths = {
  styles: {
    src: ['src/sass/**/*.scss'],
    dest: outputDir + 'css/'
  },
  scripts: {
    src: ['src/scripts/vendors/*.js','src/scripts/*.js'],
    dest: outputDir + 'js/'
  }
};

/* css */ 
function styles(cb) {

  return gulp.src(paths.styles.src)
    .pipe(sass().on('error', sass.logError))
    .pipe(gulp.dest(paths.styles.dest));

    cb();
}

/* JavaScript */ 
function scripts(cb) {
  return gulp.src(paths.scripts.src, { sourcemaps: true })
    .pipe(gulp.dest(paths.scripts.dest))

    cb();
}

function watch(cb) {
  gulp.watch(paths.scripts.src, scripts);
  gulp.watch(paths.styles.src, styles);

  cb();
}

var build = gulp.parallel(styles, scripts, watch);

exports.styles    = styles;
exports.scripts   = scripts;
exports.watch     = watch;
exports.build     = build;

/*
 * Define default task that can be called by just running `gulp` from cli
 */
exports.default   = build;

dlmanning / gulp-sass

SASS Partials not compiling on some changes #734