MembersInjectors are only called once per type instead of once per instance

Using Guice 4.2.2
I have set up a custom injector using the example in the [documentation](https://github.com/google/guice/wiki/CustomInjections), registering a `MembersInjector` into the `TypeEncounter` (exactly like in the documentation).

If I have a type requiring custom injection (we're using `Matchers.any()`, so I mean only types that a field was discovered in with my custom annotation, and a `MembersInjector` was registered for the encounter) that was instantiated multiple times - only the first one has the registered `MembersInjector`s called for.

According to the documentation linked above (emphasis mine):

> MembersInjectors and InjectionListeners can be used to receive a callback after Guice has injected an **instance**. [...] Since they're notified once-per-instance, these should execute as quickly as possible.

If I register an `InjectionListener` then everything works - the listener is called once for each instance. Also, obviously, this is not a problem if the injected type is marked as `@Singleton`.