Quasar CLI -modern Nullish coalescing operator throws error

[bjbk]

Testing out the new modern flag for an Electron app build (Electron v9.0.0) and getting a build error.
Unexpected token
The error appears at areas of code using Nullish coalescing operator ??
Removing the -modern flag and running Quasar dev -m electron then builds successfully.
Is there something about the Nullish coalescing operator that is not modern or why does it throw an error?

[Hawkeye64]

Putting here what I added on Discord

As you can see here, it was added to acorn 20 days ago in version 7.2.0
But, look here:

├─┬ @quasar/app@1.9.1
│ ├─┬ webpack@4.43.0
│ │ └── acorn@6.4.1 
│ └─┬ webpack-bundle-analyzer@3.8.0
│   └── acorn@7.2.0 
└─┬ eslint-plugin-vue@6.2.2
  └─┬ vue-eslint-parser@7.1.0
    └─┬ espree@6.2.1
      └── acorn@7.2.0  deduped

Waiting on webpack to update to v7.2.0