So I had the similar issue (it doesnt look 100% the same to me as it does for you, but very similar, and despite many re-openings of both the course and the game, it ALWAYS looked the same for me), and yes I agree that its definitely a problem on this hole... seems like it would show up with some frequency over the course of many rounds
I opened it up in APCD, looked around and experimented back and forth some, to try figure out what might be causing this issue, I hope you dont mind.
First thing I noticed was that in that direction, there is indeed lower ground, and even reflective water some 400 yards away (by 6th green). I tried a bunch of things and re-saved the course to check if things would remove or at least visibly change the appearance of the weird reflections. I tried deleting all 2d Objects on the course, I tried adding verts in the water texture, I tried changing the textures by the water edges, I tried changing all reflective water on the whole course to non-reflective water except for this one lake, I even tried detaching the whole lake from the rest of the plot, to make the water its own separate structure, neither of those things altered the reflections the least bit.
Finally, I tried selecting a bunch of brown looking textures on the whole course and changed them to something random (because the weird reflections are brown-ish), and indeed, it changed the COLOUR of the weird reflections. Then I tried to narrow down which exact area that is getting reflected, which seems to be roughly 100-150 yards towards the 6th green from the edge of the lake that is closest to the 6th green... Not exactly anywhere close to the actual (reflective) water... and a whole 300 yards or so from 7th green where we're seeing it from.
I checked different graphics settings within Links, and the weird reflections completely disappear for me when going to setting 3/6 or under on the "Picture Quality" setting. Lowering this slider does decrease the range at which things render, but at 3/6 the area which seems to be getting reflected still loads... at least in texture, so Im guessing its moreso some type of water quality effect that gets eliminated from 3/6 and below.
Another thing I noticed, which may be purely incidental, is that the reflections seem to come from straight east (what is east when opening up the course in APCD for the first time), I wonder if that possibly could be a requirement for this particular type of weird reflection to show up...
Im sad that I cant come up with any good recommendation or solution... its a real course so what are you supposed to do about it... its not like you can just raise the ground up... Maybe you'll be forced to either accept it or change to non-reflective water

I have no ideas right now, maybe tomorrow, or someone else comes up with something
