HISM rotated instance is culled whenever its pivot moves out of camera view.
Found in 4.20 CL# 4369336, 4.21 CL# 4753647, 4.22 CL# 5660361, 4.23 CL# 6037269
The mesh will disappear as soon as the pivot is out of the view frustum
The HISM would stay visible because the mesh is still in view
Set foliage.DisableCull to 1
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-73216 in the post.