On some approaches such as SFO 01R GPS Approach & SFO 01L approach, the glide slope indicator is incorrect. There is high terrain blocking the glide slope to the runway. Hence the glide slope should be steeper to ensure a safe approach to the runway.
If you fly the glide slope indicator, especially in low visibility conditions on 01L you will have controlled flight into terrain (CFIT). I conducted a test with Approach mode autopilot turned on. The autopilot flew localizer and glideslope perfectly and was about to take me straight into a mountain. You can hear the radar altimeter announcing altitudes well below 500 ft on both approaches.
SFO might not be the only airport with this bug, there might be ILS approaches as well at other airports that also have this issue.
If you can look into this that would be appreciated.