Billboard trees render queue

Hello,
I have problem with billboards, yes I know that they have render queue transparent - 100 but the actual problem is, they are always wrong. If the renderqueue is lower (transparent - 110 for example) they seemed to be OK from one side, but now when looking through the transparent object, billboard trees appear over it, but when I set it higher, the object appear over it. I smell that there is something wrong with unity rendering, because this should have been handeled by default, without any need to change anything.

Any ideas?

LEFT: object renders over billboard trees RIGHT: trees render over object

24874-image.jpg

I solved it but I don’t know what happened under-hood. I set render queue the same, it did not work before but it works now. No idea how, but it works.