My bet is that it's just bug with city build & plot order management.
It may not be the easiest task to do properly, but shaglio also exagerates a bit, especially saying it's all work for one wonder when every regular programmer would see most of it can be boiled down to generalizable value evaluation that can be used for all wonders, even districts etc - telling AI not to build it on isolated lake isn't "lines of code", it's literally just number value assigned to each plot based on adjacency, not a rocket science, not long code - the game already does similar evaluation when deciding which plot to take by Culture, it assigns Cost to plots (or at leats did so in V) and the Cost is based on what the plot holds, distance, rings, adjacency etc.
The hard part is to implement it in way that would be optimal. Pretty sure If they really wanted they could make hella smart AI that makes smart moves every turn by evaluating practically everything as things change, but who wants to wait 1+ minutes for their Turn. Someone in YT section already mentoined that they noticed that units in war seem to move based on strategy established prior to it, so they saw enemy civilian units casually walking through their territory because they were passing city that was not there before. It's possible some of these decision-locks had to be implemented because the tests showed the game can't handle doing too much decision-making too often. Or maybe they're lazy and went with limited implementations.
My fear would not be lines of code but process time. You could easily determine value of each placement-sensitive wonder. In case of Huey, you literally just count amount of lake plots say within 6 plots of each city, dynamically, increasing Attractivness of it which would determine whether AI will consider building it, then each lake plot would have value based on adjacent lakes so that AI would recognize most lucrative choice. There goes the part that all of this is calculations for one Wonder and they stretch far If one wants AI to plan into future (settle city specifically because of "lake value", planning to build Huey), ideally each AI would have to do many of these evaluations constantly. Not programmer work for one wonder, but process time for one wonder. Whether it's more possible than I imagine or not would be better said by optimization experts, optimization really never was my cup of tea, but my point generally is that it's question of what the machine can handle rather than lines of code. In terms of lines of code, the system can be boiled down into being pretty simple yet at least averagely effective by just plot values.
Back to explanation, I would guess that exactly the AI already has established plan for what it wants to do with the plots and so it considers the lake plots to be "taken". It that way may be matter of wrongly placed priorities. Or perhaps, ironically, the AI determined that it needs not the Amenities and prefers the Fisheries to be clumped for safety or plans to build TS adjacent to the Huey, but that may be me overestimating it.
I would note though that AI acting properly should not be put aside as not worth the invesment, since it's huge part of the game. The game seems more focus on Single-Player and it's not Cities Skylines, so decent AI should've been priority early in development with all it brings.