Better a Fail Warn in View than a False Indication
I'll be posting a fairly thorough explanation of the Radio Altimeter within a few days. Meanwhile, consider this:
If a sensor, such as the radio altimeter, is giving you erroneous information, you have the option to disengage its circuit breaker. That way, your brain won't be trying to integrate erroneous, nonsensical data, and further bogus alerts will be silenced. . The automatics such as GPWS, autopilot and autothrottle won't be relying on false data, either. They will look to the backup sensor, if equipped.
If radio altitude errors persist, such as reported at THY, then the C check and corrosion control programs should be reviewed.
GB