AI did an interesting thing by minute 24. Best as I can figure out:

They decided they wanted to get 2nd factories, and chose shipyards
They chose to build them in the center puddle (not what I would usually recommend, but I get it, it can be hard to know if this is a good ocean and it must be important if it is in the map center, right?)
They decided they needed caretakers to assist construction and had trouble finding a good spot. They settled on the beaches across the isthmus on either side next to nothing else, just into the water.
Their main factories got destroyed and they suddenly had metal they didn't want to excess. The build a few locations and manage to build more poorly positioned caretakers next to the poorly positioned caretakers.
A few cycles of this and they have 20% of their metal in poorly positioned (practically useless) caretakers and.... 30% of their metal in ships in the puddle, predominantly submarines


Not sure if this is worth a bug or what but at least I'll let others know there is a small laugh to be had in the replay