Re: What about the integrated standby instrument system
No, the backups wouldn't be receiving any runway information and would be immune to this bug. Most airliners will use mechanical backups and the few that have switched to glass backups are air-gapped from the rest anyway; usually equipped with their own AHRS/ADIRS units, pitot-static probes, backup batteries, etc.
I've also been seeing a lot of pilots carrying portable equipment lately. Personally, I carry a Garmin Aera 660 (GPS navigator and EFB), a Dynon D2 (GPS-derived Attitude, altitude, air speed, etc), and a Sporty's SP-400 (Comm radio with nav capabilities, including ILS). Essentially a full-panel between them; so long as the controls respond, I can land it.