Some ionic style are not properly loaded

Ionic Framework
4

Disclaimer: I know absolutely nothing about React.

My initial suspicion is that you have a race condition with a side order of uncaught exception.

At least with Angular, there are many situations where my app code gets called in the middle of what is effectively a framework execution context, like:

lifecycleEventHandler() {
  doSomethingWith(this.jankilyInitializedProperty.ruhroh);
}

someOtherFunction() {
  doAsynchronousThing().then((foo) => this.jankilyInitializedProperty = foo);
}

If doAsynchronousThing completes before lifecycleEventHandler gets called, everything works great and you don’t notice a thing. If it doesn’t, an exception will be thrown when you try to access the ruhroh property of undefined. If lifecycleEventHandler was called as part of some sort of framework pseudocode like:

frameworkInternals(compo: Component) {
  compo.lifecycleEventHandler();
  attachStyles(compo);
}

…and lifecycleEventHandler throws an uncaught exception, attachStyles never gets run, and you end up with broken styling, unresponsive controls, &c.

With Angular, there are things you can set in tsconfig.json that will turn these sorts of bugs into build-time errors, allowing you to audit your code for such problems in a more deterministic fashion than simply waiting for them to bite you.