In the case of something like this ANY corrosion is excessive.
If you don’t know what the safety factor is then it is ZERO.
If the corrosion is pitting in nature and the safety factor for corrosion is not specified the safety factor is ZERO.
Yep, VERY problematic.
I’ve heard from a participant, principal engineer that the Hoover Dam had a safety factor of 10.
They wanted to be able to build more damns over the years....