Grass disappeared!!!

[rollingfarm]

so i start playing on Blickling Hall Farm V2 and was enjoying it till this issue occurred. firstly this issue happens with both crops and grass but more annoying with grass. So to issue when cutting the grass is huge squares start flashing and disappear come out came for 5 mins or so and when back and all the mown grass was gone.l this happens with crows huge area just disappear nothing in the log so any help?