This sounds like an issue with how the game decides whether qhapaq nan's and mountain tunnels are "in the same mountain range". Unfortunately there is no way that I can fix this issue directly or even confirm that Got Lakes is the root cause.

I suspect that the various ways that Got Lakes can generate mountain ranges and then remove some of the mountains leads to mountain ranges that could *in theory* confuse the game with respect to mountain tunnels.

In fact, a few years ago someone reported that two mountain tunnels from different mountain ranges were behaving as if they were in the same range. But that was years ago.

So far I haven't had much luck in reproducing/diagnosing this issue. Maybe I'll try to look for it in my current game.

Originally posted by Scrum Lord:

This sounds like an issue with how the game decides whether qhapaq nan's and mountain tunnels are "in the same mountain range". Unfortunately there is no way that I can fix this issue directly or even confirm that Got Lakes is the root cause.

I suspect that the various ways that Got Lakes can generate mountain ranges and then remove some of the mountains leads to mountain ranges that could *in theory* confuse the game with respect to mountain tunnels.

In fact, a few years ago someone reported that two mountain tunnels from different mountain ranges were behaving as if they were in the same range. But that was years ago.

So far I haven't had much luck in reproducing/diagnosing this issue. Maybe I'll try to look for it in my current game.

Thanks for the reply. I'm happy to provide screenshots and/or files if it would help?

Here is the sort of thing I'm experiencing:
https://imgur.com/a/R0CetzP

@Scitinz thanks for the screenshots!

For the 1st one, it looks like there might be a river between your capital and its adjacent qhapaq nan. So maybe the route through the mountains costs more movement points than you think? Looks like 4 tiles that might have roads vs tunnel + river crossing to your capital.

Either that or the game's routing can't tell that the tunnel is faster. Sometimes the game recommends suboptimal routes, or doesn't calculate things like embarking/disembarking correctly, so it wouldn't surprise me if the tunnel route was considered "longer" just because it was "less direct" than the road.

For the 2nd one, not sure why the lower qhapaq nan didn't work. Sounds like another weird routing quirk.