Why does the app say sent when nothing appears in my glasses?
Sent may mean that the app queued or transmitted a command. It does not necessarily mean the frame received, rendered and displayed it. The interface needs to distinguish those events.
Follow the acknowledgment as far as it goes
Look for a request ID and a device-level acknowledgment where the protocol supports them. A successful network or Bluetooth write can still precede a rendering error or a superseded screen. The word sent should describe the event actually observed.
Use a distinctive short message and inspect whether it was queued, delivered and made visible. If the protocol cannot report display completion, say that limitation in the diagnostic record. Do not convert the absence of an error into proof that the wearer saw the content.