Can executing the same request repeatedly lead to a change in the server state while keeping it unchanged for subsequent calls?

Yes, this is possible and is related to the concept of idempotency in web services. An idempotent request is a request that, when repeated, does not change the server's state after the first call, meaning subsequent calls do not lead to additional changes.

For example, the HTTP method PUT is usually idempotent: if you send a request to update a resource with the same data multiple times, the state of the resource will remain the same after the first update.

Example:

PUT /users/123
{
  "name": "Ivan"
}

If you perform this request multiple times in a row, the user's name will remain "Ivan" and will not change further.

Thus, executing the same request repeatedly can change the server's state once, and then keep it unchanged in subsequent calls.