So i've used the Medium Tree & the Big Tree in my UEFN, It has the same bug in Creative 1.0 as well, I've shown the example in the video
it disappears at the certain distance of where you are.
Another separate bug that been in the game since UEFN first came out but for the regular Chapter 2 Nature Gallery (Variant Foliage Gallery A) You can't change the color of them in the editor.