
More screenshots of this issue can be found here: viewtopic.php?f=372&t=98999
This problem only applies to water tiles, all land tiles are rendered fine.
When I reduce the "Render Quality" setting to "Good" or lower, the rendering issue is gone and everything looks fine (but less detailed of course):

I have no issues with other games. My rig: Intel Core i5-8600K, ASUS GeForce RTX 2060, resolution set to 2560 x 1080, all drivers are up-to-date.