I've had this happen to me at random times on different maps before. It drove me nuts. If you Google search, you'll see that many people have experienced this and last I checked, there really wasn't an answer for it that I knew. I do know exactly what you are talking about and it is maddening. I've experienced it on base game maps before even.
Viewing post in FS25 - Ray County, Missouri comments
Generally, what I have seen and noticed helping people out when they have this issue it comes down to your VRAM on your card being maxed out, or close to maxed out. This game eats up VRAM.
The general fixes are tweaking graphics settings. The two biggest performance hits are your draw distances and shadows. I have personally messed with both and seen significant increase in performance while maintaining visual quality. The textures on the finer details are the first things to start getting blurry.