Run the check
Press the affected key and record KeyboardEvent.code and displayed key value.
Check the active language, input method, and app-specific shortcut or remap.
Compare a second plain text field using the same layout.
Read the result
Correct physical codes with unexpected characters point first to layout or text conversion.
Limits and next step
The page sees the active browser layout, not the printing on a keycap.
Repeat the check after changing one setting or connection. Keep a record of what changed before deciding whether the device needs service.