Stainless Strut? Like Faster, I did not know that they existed...
What kind of boat is it?
My O'day has a bronze strut, not attached to the bonding system either.
Here is a pic;
The shaft is a 1" bronze shaft. The prop has a 1¼" id, and there is a nylon bushing between the shaft and the prop, thus electrically isolating the two. The prop has NO issue with corrosion, despite evidence elsewhere that the boat had galvanic corrosion issues.
Were your boat mine, I would be looking to replace the entire strut.