red warning text on build

[quetzalsly]

00:50:51 [build] Building static entrypoints...
(node:11544) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
(Use `node --trace-warnings ...` to show where the warning was created)
(node:11544) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
00:50:54 [astro-icon] Loaded icons from flat-color-icons, tabler

Is this supposed to happen during build? it wants .mjs somewhere?
I am not sure how to debug this.
I also have "type": "module" in the package.json but it still gives the warning.