conflicting peer: rollup

[NullVoxPopuli]

I'm doing a mass upgrade of my empress site -- and am just reporting some things I'm running in to:

 WARN  Issues with peer dependencies found
.
└─┬ empress-blog-casper-template
  └─┬ ember-responsive-image
    ├─┬ @rollup/plugin-commonjs
    │ ├── ✕ missing peer rollup@^2.38.3
    │ └─┬ @rollup/pluginutils
    │   └── ✕ missing peer rollup@^1.20.0||^2.0.0
    ├─┬ @rollup/plugin-node-resolve
    │ └── ✕ missing peer rollup@^1.20.0
    └─┬ rollup-plugin-terser
      └── ✕ missing peer rollup@^2.0.0
✕ Conflicting peer dependencies:
  rollup  

After installing rollup in my app (due to the missing peer message) ( and I don't know what it would be used for):

└─┬ empress-blog-casper-template
  └─┬ ember-responsive-image
    └─┬ @rollup/plugin-node-resolve
      └── ✕ unmet peer rollup@^1.20.0: found 2.76.0

seems ember-responsive-image needs some old rollup

Is this some build time behavior that runs in empress apps? or is it an accidental leak? (solved by adding rollup as a dependency in ember-responsive-image?)