For one reason or another, the trade route durations are super inaccurate for me - multiple times of what I'd expect.

As an example, this game is on standard speed, my first trade route, and yet I'm seeing times around thirty turns - I'd expect something under ten, perhaps low teens. https://imgur.com/a/23voLBk

I'm playing on Linux, using the Windows version through Proton. Can give more details as necessary, just don't know which.