Yes. perhaps its just sleeping, and will wake up when you send a command. This is a generic design philosophy, not all technologies are alike.
That’s correct. But you do have autoupdate enabled on this Item. (It’s enabled by default).
In the interests of a snappy UI, it predicts the likely outcome of a command and updates the Item state.
If you don’t like that, disable autoupdate. The Item state will then only get updated when a “real” response arrives.
Is it polled regularly, or does it report unsolicited periodically? Then you can detect those periodic updates and ring a bell when one or more is missing.
The expire binding was created for this purpose, but there are other ways. The Item state UNDEF is useful in this context, to indicate “failed”.
This old thread covers the general idea
Or, you might start/restart a watchdog timer on each update. if that ever expires, ring a bell.
If you wanted, “ring a bell” action could include force disabling of your Thing. Might be useful where are several channels on a device, but the effect that has on any linked Items depends on the binding. You’d need to think about recovery too.
If you like. It won’t change openHAB behaviour.