P Bracket de-zincing

[SJFK]

Hi everyone
I am looking to get some insight as to why the P Bracket on my Wauquiez 43 Pilot Saloon is de-zincing (pinking). It is a French built yacht and there is no bonding evident for any of the fittings, so everything is isolated. The prop shaft has an anode fitted, as does the Gori propeller with a collar anode and a small tricorn anode on the hub. I also fitted a small anode direct to the P Bracket itself as last year I noted that de-zincing was beginning to show. This year it is even more evident. All the anodes have eroded so they seem to be working. I wonder if the screws holding the anodes on might be having an effect; they are all stainless steel. It could also be the marina shore power supply or the other boats in the marina I am in which is having a detrimental effect.
I would really appreciate any advice or help to understand what is going on.
Many thanks