Landscape collision is very inaccurate

Hello everyone!
I am having a very annoying issue at the moment. I imported a landscape and the settings for the size are as follow:


The problem is that in slopes, the collision is completely messed up. The player passes through it, almost causing the camera to go under the visual ground, because the collision is quite off in slopes. I checked and collision mip levels are at 0, so collision accuracy should be at its maximum. It is also not a player collision problem because grass (placed by the landscape’s material) is floating above the landscape, as well as manually placed foliage. The effects are the following:

I did not find anything on the internet but it also happened on another project I made, but I don’t know what to do to solve it. Anyone has any ideas?
Thanks in advance!

I have same issue with massive world 6000px x 6000 px and just increase number from complex and simple LOD from 0 to 2 can solve it. LOD 0 much accurate but sometime give leak collision because engine can’t calculate in massive area.