What does offline navigation in smart glasses require?
Offline navigation needs the route and map resources required by the feature to be available locally, along with a usable estimate of current location. It may also need the phone-to-glasses connection. Different applications support different parts of this workflow without internet.
Starting a route and recovering it are separate capabilities
A previously loaded route might remain visible while a new destination or recalculation still requires a network. Likewise, a cached map image does not establish that routing can operate offline. The useful test includes what happens after you leave the planned path.
Test a fresh route start, progress along the route and a deviation without internet. Keep the supported local device connection active if the feature requires it, so a test of internet independence does not accidentally become a different test of phone independence.