Forward rendering + MSAA + opacity = issue

My setup:
4.22.3 (also 4.21, 4.20)
Forward render enabled, masked materials with opacity textures.
r.DefaultFeature.AntiAliasing set to 3

when i switch:

r.MSAACount set to 0. Result: everything rendered correctly.

r.MSAACount set to 1. Result: Antialiasing getting worse.

r.MSAACount set to 2. Result: Tree rendrering incorrect.

r.MSAACount set to 4. Result: Tree rendering translucent.

r.MSAACount set to 8. Result: Tree and fence rendering translucent.

Multiply your opacity mask with 2 or a higher number.