When you mean "AEM React SPA": are you using the SPA Editor feature of AEM? There I would wonder if this happens.
Thus you likely have a standard component, which is using React to render. And in that case I wonder why the mentioned examples cannot are not working.
For AEM your component is not special in any way. Have you tried with a very rudimentary, non-React component? Does it work there?
Jörg