Yes, I concur as well. My first boat was a 12 foot Duracraft rowboat. The PO had replaced the transom wood with pressure treated lumber. It was a sad looking job, so I replaced it again myself after getting the boat. When I removed the wood that was on it many holes had been eaten through the aluminum transom. I did a bit of research as I was doing this work as this was my first time doing it. I found out quickly about the effect of pressure treated lumber on aluminum. When I replaced it I used hardwood inside and a piece of construction grade plywood outside. several coats of outdoor polyurethane on both boards prior to replacement. I used 100% silicone caulk to seal the outer board and all the bolt holes when I put it back together. it didn't leak and it was only rated for 8hp. It had a Merc 9.8 on it and I ran it that way one time before I bought a bigger boat. It held the 9.8 OK, but being a newbie at the time, that was way too much motor on that boat for me. I see visions of that Swiss cheese transom every time I think of pressure treated lumber.
YouTube handle: Old JohnnyRude