This is expected. The OAuth spec defines two client types -- confidential clients (eg. web apps) "capable of maintaining the confidentiality of their credentials" and public clients (eg. native apps) "incapable of maintaining the confidentiality of their credentials". https://datatracker.ietf.org/doc/html/rfc6749#section-2.1
> A native application is a public client installed and executed on the device used by the resource owner ... It is assumed that any client authentication credentials included in the application can be extracted
> A native application is a public client installed and executed on the device used by the resource owner ... It is assumed that any client authentication credentials included in the application can be extracted