Does anyone know why this occurs?
When I look through the glass I cant see the top of the trees?
I found this by some roblox announcement if it may help you.
Warning: Non-opaque Objects - Non-opaque objects are currently not visible through glass. This includes, but is not limited to, transparent parts, decals on transparent parts, particles, and world-space gui objects. This behavior matches the refraction on high quality smooth terrain water. This was implemented so refraction wouldn’t have a large performance impact. This behavior may change. We do not recommend relying on this behavior for gameplay.
Adding on to what @jumpyfunk said:
I’d suggest changing the material to ice with a 0.75 transparency. It’s the closest I could get.
click on the tree leaves and see if there is a option called “alwaysontop” or something similar. I’ve used it sometimes for guis.
Images/Texts (UIs) are invisible through glass (same how is the text from sign block through glass block in Build a boat for treasure)
Best way to save from this is to create a surfaceappearence in the mesh part and put the leaf texture in color map and transparency to 0 and change alpha to transparency