Why does my terrain vanish in just one viewport when I zoom out?

Hi people, made a basic landscape with a flat terrain. Basically, it shows up fine when I’m close to it in viewport 1 but as soon as I move the camera back the whole thing starts to disappears by chunks. what’s weird is this only happens in that one viewport 1.. If I look at it from viewport 2 or any other it behaves normally and doesn’t vanish at all … here’s a quick video showing it … you’ll see how the terrain stays visible in viewport 2 but in viewport 1 its portions just blink out when I pull back the camera..

I turned off world partition streaming tweaked all the landscape settings I could find messed with project settings LODs and tried everything I could think of but still the same issue.. This bothers me because I want to see fully the terrain even in the background as per my needs to track the background view from the camera giving me really insights on what the camera will record during sequence animation. Now I don’t know, it kinda feels like it’s only showing the parts of the terrain that are close up, like maybe some pixel depth thing or clipping or something, but really I’m not sure what it is
Could be a bug perhaps, could be some setting hiding somewhere…
So if anyone knows what’s going on here or if it’s just some weird viewport thing, let me know please.