"expo publish" not working for app built with EAS + expo-dev-client

I'm using the new expo-dev-client and EAS workflow to attempt development with expo, while also including native dependencies (react-native-firebase in my case).

I've managed to build and install a preview of my app with EAS:

eas build --platform ios --profile staging

Where my "staging" profile is setup in eas.json like so:

{
   "cli": {
      "version": ">= 0.35.0"
   },
   "build": {
      "production": {
         "releaseChannel": "prod-v0",
         "node": "14.17.4",
         "ios": {
            "cocoapods": "1.11.2",
            "autoIncrement": "buildNumber"
         }
      },
      "staging": {
         "extends": "production",
         "releaseChannel": "staging",
         "distribution": "internal"
      },
      ...
   },
   ...
}

Note the releaseChannel is set to "staging" too.

So far so good. The app is building and I can install it on my device and confirm the releaseChannel using the expo-updates module with Updates.releaseChannel

Now I'd like to publish a pure javascript change, so I run...

expo publish --release-channel staging

But this gives the following warning (which I assume is why I don't see the update on my device):

ios: Expo.plist key: "EXUpdatesReleaseChannel": The value passed to the 
--release-channel flag is to "staging", but it is set to "default".

So what/where is "Expo.plist", why isn't it in-sync, and how can I update it?

Update:

So I deleted the iOS folder from a previous expo run:ios build. The warning is now gone when running expo publish --release-channel staging. But still nothing seems to happen on my app - it still doesn't update.