Does airplane mode prove a glasses feature is offline?
It is a useful control only when you know which connections remain enabled. Phone settings can leave or restore particular radios, so the label alone is not a complete description of the test condition.
Record the connections you actually disabled
Distinguish cellular and Wi-Fi internet from the local Bluetooth link to the glasses. You may want to keep the local link while removing internet to test phone-connected offline use. Removing every radio tests a different architecture.
After setting the condition, make a fresh request rather than reopening the last answer. Record which devices are present and which connections are available. This makes the result interpretable and prevents a cached screen from being mistaken for successful new processing.