Hey there @Hmmedina! Welcome to the community! It could be distance based culling. So for your static meshes you can disable distance culling or change it’s values in the LOD section of the actor’s details:
For foliage, you’ll have to open up the foliage asset and change it’s cull distance values here:
If you have larger scenes you may want larger values.
If it’s not distance based culling, let me know and we can dig a bit deeper!